Write a RationalNumber class.

.gitignore

@@ -24,9 +24,7 @@ hs_err_pid*
 # Custom Stuff
 # Gradle
 .gradle/*
-**/build/*
+build/*
-**/out/**
-**/.DS_Store
 
 # IntelliJ
 .idea/*

build.gradle

@@ -1,29 +1,22 @@
-buildscript {
+plugins {
-    ext.kotlin_version = '1.1.3'
+    id 'java'
-    ext.dokka_version = '0.9.15'
+    id 'application'
-
+    id 'org.jetbrains.kotlin.jvm' version '1.1.3'
-    repositories {
-        jcenter()
-    }
-
-    dependencies {
-        classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:$kotlin_version"
-        classpath "org.jetbrains.dokka:dokka-gradle-plugin:$dokka_version"
-    }
 }
+apply plugin: 'java'
+apply plugin: 'application'
 
-subprojects {
+repositories {
-
-    apply plugin: 'java'
-    apply plugin: 'kotlin'
-    apply plugin: 'org.jetbrains.dokka'
-
-    repositories {
   mavenCentral()
-    }
-
-    dependencies {
-        compile "org.jetbrains.kotlin:kotlin-stdlib-jre7:1.1.3"
-    }
 }
 
+dependencies {
+    compile group: 'org.apache.commons', name: 'commons-math3', version: '3.6.1'
+    compile 'com.moandjiezana.toml:toml4j:0.7.1'
+    compile "org.jetbrains.kotlin:kotlin-stdlib-jre8"
+    testCompile 'junit:junit:4.12'
+}
+
+// Define the main class for the application
+mainClassName = 'org.nwapw.abacus.Abacus'
+

core/build.gradle

@@ -1,3 +0,0 @@
-dependencies {
-    testCompile 'junit:junit:4.12'
-}

core/src/main/java/org/nwapw/abacus/exception/AbacusException.java

@@ -1,9 +0,0 @@
-package org.nwapw.abacus.exception;
-
-public class AbacusException extends RuntimeException {
-
-    public AbacusException(String baseMessage, String description){
-        super(baseMessage + ((description.equals("")) ? "." : (": " + description)));
-    }
-
-}

core/src/main/java/org/nwapw/abacus/exception/ComputationInterruptedException.java

@@ -1,16 +0,0 @@
-package org.nwapw.abacus.exception;
-
-/**
- * Exception thrown when the computation is interrupted by
- * the user.
- */
-public class ComputationInterruptedException extends AbacusException {
-
-    /**
-     * Creates a new exception of this type.
-     */
-    public ComputationInterruptedException() {
-        super("Computation interrupted", "");
-    }
-
-}

core/src/main/java/org/nwapw/abacus/exception/DomainException.java

@@ -1,24 +0,0 @@
-package org.nwapw.abacus.exception;
-
-/**
- * Exception thrown if the function parameters do not match
- * requirements.
- */
-public class DomainException extends AbacusException {
-
-    /**
-     * Creates a new DomainException.
-     * @param reason the reason for which the exception is thrown.
-     */
-    public DomainException(String reason) {
-        super("Domain error", reason);
-    }
-
-    /**
-     * Creates a new DomainException with a default message.
-     */
-    public DomainException(){
-        this("");
-    }
-
-}

core/src/main/java/org/nwapw/abacus/exception/EvaluationException.java

@@ -1,25 +0,0 @@
-package org.nwapw.abacus.exception;
-
-/**
- * An exception thrown primarily from Tree Value operators and functions,
- * which have to deal with the result of a Reducer as well as the results
- * of Applicable.
- */
-public class EvaluationException extends AbacusException {
-
-    /**
-     * Creates a new EvaluationException with the default string.
-     */
-    public EvaluationException() {
-        this("");
-    }
-
-    /**
-     * Creates a new EvaluationError with the given message string.
-     * @param message the message string.
-     */
-    public EvaluationException(String message) {
-        super("Evaluation error", message);
-    }
-
-}

core/src/main/java/org/nwapw/abacus/function/DocumentationType.java

@@ -1,11 +0,0 @@
-package org.nwapw.abacus.function;
-
-/**
- * Enum that holds the type of documentation that has been
- * registered with Abacus.
- */
-public enum DocumentationType {
-
-    FUNCTION, TREE_VALUE_FUNCTION
-
-}

core/src/main/java/org/nwapw/abacus/plugin/StandardPlugin.java

@@ -1,839 +0,0 @@
-package org.nwapw.abacus.plugin;
-
-import org.nwapw.abacus.context.MutableEvaluationContext;
-import org.nwapw.abacus.function.*;
-import org.nwapw.abacus.number.NaiveNumber;
-import org.nwapw.abacus.number.NumberInterface;
-import org.nwapw.abacus.number.PreciseNumber;
-import org.nwapw.abacus.tree.TreeNode;
-import org.nwapw.abacus.tree.VariableNode;
-
-import java.util.ArrayList;
-import java.util.HashMap;
-
-/**
- * The plugin providing standard functions such as addition and subtraction to
- * the calculator.
- */
-public class StandardPlugin extends Plugin {
-
-    /**
-     * The set operator.
-     */
-    public final TreeValueOperator opSet = new TreeValueOperator(OperatorAssociativity.LEFT, OperatorType.BINARY_INFIX, 0) {
-        @Override
-        public boolean matchesParams(MutableEvaluationContext context, TreeNode[] params) {
-            return params.length == 2 && params[0] instanceof VariableNode;
-        }
-
-        @Override
-        public NumberInterface applyInternal(MutableEvaluationContext context, TreeNode[] params) {
-            String assignTo = ((VariableNode) params[0]).getVariable();
-            NumberInterface value = params[1].reduce(context.getInheritedReducer());
-            context.setVariable(assignTo, value);
-            return value;
-        }
-    };
-    /**
-     * The define operator.
-     */
-    public final TreeValueOperator opDefine = new TreeValueOperator(OperatorAssociativity.LEFT, OperatorType.BINARY_INFIX, 0) {
-        @Override
-        public boolean matchesParams(MutableEvaluationContext context, TreeNode[] params) {
-            return params.length == 2 && params[0] instanceof VariableNode;
-        }
-
-        @Override
-        public NumberInterface applyInternal(MutableEvaluationContext context, TreeNode[] params) {
-            String assignTo = ((VariableNode) params[0]).getVariable();
-            context.setDefinition(assignTo, params[1]);
-            return params[1].reduce(context.getInheritedReducer());
-        }
-    };
-    /**
-     * The addition operator, +
-     */
-    public static final NumberOperator OP_ADD = new NumberOperator(OperatorAssociativity.LEFT, OperatorType.BINARY_INFIX, 0) {
-        @Override
-        public boolean matchesParams(MutableEvaluationContext context, NumberInterface[] params) {
-            return params.length == 2;
-        }
-
-        @Override
-        public NumberInterface applyInternal(MutableEvaluationContext context, NumberInterface[] params) {
-            return params[0].add(params[1]);
-        }
-    };
-    /**
-     * The subtraction operator, -
-     */
-    public static final NumberOperator OP_SUBTRACT = new NumberOperator(OperatorAssociativity.LEFT, OperatorType.BINARY_INFIX, 0) {
-        @Override
-        public boolean matchesParams(MutableEvaluationContext context, NumberInterface[] params) {
-            return params.length == 2;
-        }
-
-        @Override
-        public NumberInterface applyInternal(MutableEvaluationContext context, NumberInterface[] params) {
-            return params[0].subtract(params[1]);
-
-        }
-    };
-    /**
-     * The negation operator, -
-     */
-    public static final NumberOperator OP_NEGATE = new NumberOperator(OperatorAssociativity.LEFT, OperatorType.UNARY_PREFIX, 0) {
-        @Override
-        public boolean matchesParams(MutableEvaluationContext context, NumberInterface[] params) {
-            return params.length == 1;
-        }
-
-        @Override
-        public NumberInterface applyInternal(MutableEvaluationContext context, NumberInterface[] params) {
-            return params[0].negate();
-        }
-    };
-    /**
-     * The multiplication operator, *
-     */
-    public static final NumberOperator OP_MULTIPLY = new NumberOperator(OperatorAssociativity.LEFT, OperatorType.BINARY_INFIX, 1) {
-        @Override
-        public boolean matchesParams(MutableEvaluationContext context, NumberInterface[] params) {
-            return params.length == 2;
-        }
-
-        @Override
-        public NumberInterface applyInternal(MutableEvaluationContext context, NumberInterface[] params) {
-            return params[0].multiply(params[1]);
-        }
-    };
-    /**
-     * The implementation for double-based naive numbers.
-     */
-    public static final NumberImplementation IMPLEMENTATION_NAIVE = new NumberImplementation(NaiveNumber.class, 0) {
-        @Override
-        public NumberInterface instanceForString(String string) {
-            return new NaiveNumber(string);
-        }
-
-        @Override
-        public NumberInterface instanceForPi() {
-            return new NaiveNumber(Math.PI);
-        }
-    };
-    /**
-     * The implementation for the infinite-precision BigDecimal.
-     */
-    public static final NumberImplementation IMPLEMENTATION_PRECISE = new NumberImplementation(PreciseNumber.class, 0) {
-        @Override
-        public NumberInterface instanceForString(String string) {
-            return new PreciseNumber(string);
-        }
-
-        @Override
-        public NumberInterface instanceForPi() {
-            MutableEvaluationContext dummyContext = new MutableEvaluationContext(null, this, null);
-            NumberInterface C = FUNCTION_SQRT.apply(dummyContext, new PreciseNumber("10005")).multiply(new PreciseNumber("426880"));
-            NumberInterface M = PreciseNumber.ONE;
-            NumberInterface L = new PreciseNumber("13591409");
-            NumberInterface X = M;
-            NumberInterface sum = L;
-            int termsNeeded = C.getMaxPrecision() / 13 + 1;
-
-            NumberInterface lSummand = new PreciseNumber("545140134");
-            NumberInterface xMultiplier = new PreciseNumber("262537412")
-                    .multiply(new PreciseNumber("1000000000"))
-                    .add(new PreciseNumber("640768000"))
-                    .negate();
-            for (int i = 0; i < termsNeeded; i++) {
-                M = M
-                        .multiply(new PreciseNumber((12 * i + 2) + ""))
-                        .multiply(new PreciseNumber((12 * i + 6) + ""))
-                        .multiply(new PreciseNumber((12 * i + 10) + ""))
-                        .divide(new PreciseNumber(Math.pow(i + 1, 3) + ""));
-                L = L.add(lSummand);
-                X = X.multiply(xMultiplier);
-                sum = sum.add(M.multiply(L).divide(X));
-            }
-            return C.divide(sum);
-        }
-    };
-    /**
-     * The division operator, /
-     */
-    public static final NumberOperator OP_DIVIDE = new NumberOperator(OperatorAssociativity.LEFT, OperatorType.BINARY_INFIX, 1) {
-        @Override
-        public boolean matchesParams(MutableEvaluationContext context, NumberInterface[] params) {
-            return params.length == 2 && params[1].compareTo(context.getInheritedNumberImplementation().instanceForString(Integer.toString(0))) != 0;
-        }
-
-        @Override
-        public NumberInterface applyInternal(MutableEvaluationContext context, NumberInterface[] params) {
-            return params[0].divide(params[1]);
-        }
-    };
-    /**
-     * The factorial operator, !
-     */
-    public static final NumberOperator OP_FACTORIAL = new NumberOperator(OperatorAssociativity.RIGHT, OperatorType.UNARY_POSTFIX, 0) {
-        //private HashMap<Class<? extends NumberInterface>, ArrayList<NumberInterface>> storedList = new HashMap<Class<? extends NumberInterface>, ArrayList<NumberInterface>>();
-        @Override
-        public boolean matchesParams(MutableEvaluationContext context, NumberInterface[] params) {
-            return params.length == 1
-                    && params[0].fractionalPart().compareTo(context.getInheritedNumberImplementation().instanceForString("0")) == 0
-                    && params[0].signum() >= 0;
-        }
-
-        @Override
-        public NumberInterface applyInternal(MutableEvaluationContext context, NumberInterface[] params) {
-            NumberImplementation implementation = context.getInheritedNumberImplementation();
-            if (params[0].signum() == 0) {
-                return implementation.instanceForString("1");
-            }
-            NumberInterface one = implementation.instanceForString("1");
-            NumberInterface factorial = params[0];
-            NumberInterface multiplier = params[0];
-            //It is necessary to later prevent calls of factorial on anything but non-negative integers.
-            while ((multiplier = multiplier.subtract(one)).signum() == 1) {
-                factorial = factorial.multiply(multiplier);
-            }
-            return factorial;
-                /*if(!storedList.containsKey(params[0].getClass())){
-                    storedList.put(params[0].getClass(), new ArrayList<NumberInterface>());
-                    storedList.get(params[0].getClass()).add(NaiveNumber.ONE.promoteTo(params[0].getClass()));
-                    storedList.get(params[0].getClass()).add(NaiveNumber.ONE.promoteTo(params[0].getClass()));
-                }*/
-        }
-    };
-    /**
-     * The permutation operator.
-     */
-    public static final NumberOperator OP_NPR = new NumberOperator(OperatorAssociativity.RIGHT, OperatorType.BINARY_INFIX, 0) {
-        @Override
-        public boolean matchesParams(MutableEvaluationContext context, NumberInterface[] params) {
-            return params.length == 2 && params[0].fractionalPart().signum() == 0
-                    && params[1].fractionalPart().signum() == 0;
-        }
-
-        @Override
-        public NumberInterface applyInternal(MutableEvaluationContext context, NumberInterface[] params) {
-            NumberImplementation implementation = context.getInheritedNumberImplementation();
-            if (params[0].compareTo(params[1]) < 0 ||
-                    params[0].signum() < 0 ||
-                    (params[0].signum() == 0 && params[1].signum() != 0)) return implementation.instanceForString("0");
-            NumberInterface total = implementation.instanceForString("1");
-            NumberInterface multiplyBy = params[0];
-            NumberInterface remainingMultiplications = params[1];
-            NumberInterface halfway = params[0].divide(implementation.instanceForString("2"));
-            if (remainingMultiplications.compareTo(halfway) > 0) {
-                remainingMultiplications = params[0].subtract(remainingMultiplications);
-            }
-            while (remainingMultiplications.signum() > 0) {
-                total = total.multiply(multiplyBy);
-                remainingMultiplications = remainingMultiplications.subtract(implementation.instanceForString("1"));
-                multiplyBy = multiplyBy.subtract(implementation.instanceForString("1"));
-            }
-            return total;
-        }
-    };
-    /**
-     * The combination operator.
-     */
-    public static final NumberOperator OP_NCR = new NumberOperator(OperatorAssociativity.RIGHT, OperatorType.BINARY_INFIX, 0) {
-        @Override
-        public boolean matchesParams(MutableEvaluationContext context, NumberInterface[] params) {
-            return params.length == 2 && params[0].fractionalPart().signum() == 0
-                    && params[1].fractionalPart().signum() == 0;
-        }
-
-        @Override
-        public NumberInterface applyInternal(MutableEvaluationContext context, NumberInterface[] params) {
-            return OP_NPR.apply(context, params).divide(OP_FACTORIAL.apply(context, params[1]));
-        }
-    };
-    /**
-     * The absolute value function, abs(-3) = 3
-     */
-    public static final NumberFunction FUNCTION_ABS = new NumberFunction() {
-        @Override
-        public boolean matchesParams(MutableEvaluationContext context, NumberInterface[] params) {
-            return params.length == 1;
-        }
-
-        @Override
-        public NumberInterface applyInternal(MutableEvaluationContext context, NumberInterface[] params) {
-            return params[0].multiply(context.getInheritedNumberImplementation().instanceForString(Integer.toString(params[0].signum())));
-        }
-    };
-    /**
-     * The natural log function.
-     */
-    public static final NumberFunction FUNCTION_LN = new NumberFunction() {
-        @Override
-        public boolean matchesParams(MutableEvaluationContext context, NumberInterface[] params) {
-            return params.length == 1 && params[0].compareTo(context.getInheritedNumberImplementation().instanceForString("0")) > 0;
-        }
-
-        @Override
-        public NumberInterface applyInternal(MutableEvaluationContext context, NumberInterface[] params) {
-            NumberImplementation implementation = context.getInheritedNumberImplementation();
-            NumberInterface param = params[0];
-            NumberInterface one = implementation.instanceForString("1");
-            int powersOf2 = 0;
-            while (FUNCTION_ABS.apply(context, param.subtract(one)).compareTo(implementation.instanceForString(".1")) >= 0) {
-                if (param.subtract(one).signum() == 1) {
-                    param = param.divide(implementation.instanceForString("2"));
-                    powersOf2++;
-                    if (param.subtract(one).signum() != 1) {
-                        break;
-                        //No infinite loop for you.
-                    }
-                } else {
-                    param = param.multiply(implementation.instanceForString("2"));
-                    powersOf2--;
-                    if (param.subtract(one).signum() != -1) {
-                        break;
-                        //No infinite loop for you.
-                    }
-                }
-            }
-            return getLog2(context.getInheritedNumberImplementation(), param).multiply(implementation.instanceForString(Integer.toString(powersOf2))).add(getLogPartialSum(context, param));
-        }
-
-        /**
-         * Returns the partial sum of the Taylor series for logx (around x=1).
-         * Automatically determines the number of terms needed based on the precision of x.
-         * @param x value at which the series is evaluated. 0 < x < 2. (x=2 is convergent but impractical.)
-         * @return the partial sum.
-         */
-        private NumberInterface getLogPartialSum(MutableEvaluationContext context, NumberInterface x) {
-            NumberImplementation implementation = context.getInheritedNumberImplementation();
-            NumberInterface maxError = x.getMaxError();
-            x = x.subtract(implementation.instanceForString("1")); //Terms used are for log(x+1).
-            NumberInterface currentNumerator = x, currentTerm = x, sum = x;
-            int n = 1;
-            while (FUNCTION_ABS.apply(context, currentTerm).compareTo(maxError) > 0) {
-                n++;
-                currentNumerator = currentNumerator.multiply(x).negate();
-                currentTerm = currentNumerator.divide(implementation.instanceForString(Integer.toString(n)));
-                sum = sum.add(currentTerm);
-            }
-            return sum;
-        }
-
-        /**
-         * Returns natural log of 2 to the required precision of the class of number.
-         * @param number a number of the same type as the return type. (Used for precision.)
-         * @return the value of log(2) with the appropriate precision.
-         */
-        private NumberInterface getLog2(NumberImplementation implementation, NumberInterface number) {
-            NumberInterface maxError = number.getMaxError();
-            //NumberInterface errorBound = implementation.instanceForString("1");
-            //We'll use the series \sigma_{n >= 1) ((1/3^n + 1/4^n) * 1/n)
-            //In the following, a=1/3^n, b=1/4^n, c = 1/n.
-            //a is also an error bound.
-            NumberInterface a = implementation.instanceForString("1"), b = a, c = a;
-            NumberInterface sum = implementation.instanceForString("0");
-            NumberInterface one = implementation.instanceForString("1");
-            int n = 0;
-            while (a.compareTo(maxError) >= 1) {
-                n++;
-                a = a.divide(implementation.instanceForString("3"));
-                b = b.divide(implementation.instanceForString("4"));
-                c = one.divide(implementation.instanceForString(Integer.toString(n)));
-                sum = sum.add(a.add(b).multiply(c));
-            }
-            return sum;
-        }
-    };
-    /**
-     * Gets a random number smaller or equal to the given number's integer value.
-     */
-    public static final NumberFunction FUNCTION_RAND_INT = new NumberFunction() {
-        @Override
-        public boolean matchesParams(MutableEvaluationContext context, NumberInterface[] params) {
-            return params.length == 1;
-        }
-
-        @Override
-        public NumberInterface applyInternal(MutableEvaluationContext context, NumberInterface[] params) {
-            return context.getInheritedNumberImplementation().instanceForString(Long.toString(Math.round(Math.random() * params[0].floor().intValue())));
-        }
-    };
-    /**
-     * The caret / pow operator, ^
-     */
-    public static final NumberOperator OP_CARET = new NumberOperator(OperatorAssociativity.RIGHT, OperatorType.BINARY_INFIX, 2) {
-        @Override
-        public boolean matchesParams(MutableEvaluationContext context, NumberInterface[] params) {
-            NumberInterface zero = context.getInheritedNumberImplementation().instanceForString("0");
-            return params.length == 2
-                    && !(params[0].compareTo(zero) == 0
-                    && params[1].compareTo(zero) == 0)
-                    && !(params[0].signum() == -1 && params[1].fractionalPart().compareTo(zero) != 0);
-        }
-
-        @Override
-        public NumberInterface applyInternal(MutableEvaluationContext context, NumberInterface[] params) {
-            NumberImplementation implementation = context.getInheritedNumberImplementation();
-            NumberInterface zero = implementation.instanceForString("0");
-            if (params[0].compareTo(zero) == 0)
-                return zero;
-            else if (params[1].compareTo(zero) == 0)
-                return implementation.instanceForString("1");
-            //Detect integer bases:
-            if (params[0].fractionalPart().compareTo(implementation.instanceForString("0")) == 0
-                    && FUNCTION_ABS.apply(context, params[1]).compareTo(implementation.instanceForString(Integer.toString(Integer.MAX_VALUE))) < 0
-                    && FUNCTION_ABS.apply(context, params[1]).compareTo(implementation.instanceForString("1")) >= 0) {
-                NumberInterface[] newParams = {params[0], params[1].fractionalPart()};
-                return params[0].intPow(params[1].floor().intValue()).multiply(applyInternal(context, newParams));
-            }
-            return FUNCTION_EXP.apply(context, FUNCTION_LN.apply(context, FUNCTION_ABS.apply(context, params[0])).multiply(params[1]));
-        }
-    };
-    /**
-     * The square root function.
-     */
-    public static final NumberFunction FUNCTION_SQRT = new NumberFunction() {
-        @Override
-        public boolean matchesParams(MutableEvaluationContext context, NumberInterface[] params) {
-            return params.length == 1;
-        }
-
-        @Override
-        public NumberInterface applyInternal(MutableEvaluationContext context, NumberInterface[] params) {
-            return OP_CARET.apply(context, params[0], context.getInheritedNumberImplementation().instanceForString(".5"));
-        }
-    };
-    private static final HashMap<NumberImplementation, ArrayList<NumberInterface>> FACTORIAL_LISTS = new HashMap<>();
-    /**
-     * The exponential function, exp(1) = e^1 = 2.71...
-     */
-    public static final NumberFunction FUNCTION_EXP = new NumberFunction() {
-        @Override
-        public boolean matchesParams(MutableEvaluationContext context, NumberInterface[] params) {
-            return params.length == 1;
-        }
-
-        @Override
-        public NumberInterface applyInternal(MutableEvaluationContext context, NumberInterface[] params) {
-            NumberImplementation implementation = context.getInheritedNumberImplementation();
-            NumberInterface maxError = params[0].getMaxError();
-            int n = 0;
-            if (params[0].signum() < 0) {
-                NumberInterface[] negatedParams = {params[0].negate()};
-                return implementation.instanceForString("1").divide(applyInternal(context, negatedParams));
-            } else {
-                //We need n such that x^(n+1) * 3^ceil(x) <= maxError * (n+1)!.
-                //right and left refer to lhs and rhs in the above inequality.
-                NumberInterface sum = implementation.instanceForString("1");
-                NumberInterface nextNumerator = params[0];
-                NumberInterface left = params[0].multiply(implementation.instanceForString("3").intPow(params[0].ceiling().intValue())), right = maxError;
-                do {
-                    sum = sum.add(nextNumerator.divide(factorial(implementation, n + 1)));
-                    n++;
-                    nextNumerator = nextNumerator.multiply(params[0]);
-                    left = left.multiply(params[0]);
-                    NumberInterface nextN = implementation.instanceForString(Integer.toString(n + 1));
-                    right = right.multiply(nextN);
-                    //System.out.println(left + ", " + right);
-                }
-                while (left.compareTo(right) > 0);
-                //System.out.println(n+1);
-                return sum;
-            }
-        }
-    };
-    /**
-     * The sine function (the argument is interpreted in radians).
-     */
-    public final NumberFunction functionSin = new NumberFunction() {
-        @Override
-        public boolean matchesParams(MutableEvaluationContext context, NumberInterface[] params) {
-            return params.length == 1;
-        }
-
-        @Override
-        public NumberInterface applyInternal(MutableEvaluationContext context, NumberInterface[] params) {
-            NumberImplementation implementation = context.getInheritedNumberImplementation();
-            NumberInterface pi = piFor(params[0].getClass());
-            NumberInterface twoPi = pi.multiply(implementation.instanceForString("2"));
-            NumberInterface theta = getSmallAngle(context, params[0], pi);
-            //System.out.println(theta);
-            if (theta.compareTo(pi.multiply(implementation.instanceForString("1.5"))) >= 0) {
-                theta = theta.subtract(twoPi);
-            } else if (theta.compareTo(pi.divide(implementation.instanceForString("2"))) > 0) {
-                theta = pi.subtract(theta);
-            }
-            //System.out.println(theta);
-            return sinTaylor(context, theta);
-        }
-    };
-    /**
-     * The cosine function (the argument is in radians).
-     */
-    public final NumberFunction functionCos = new NumberFunction() {
-        @Override
-        public boolean matchesParams(MutableEvaluationContext context, NumberInterface[] params) {
-            return params.length == 1;
-        }
-
-        @Override
-        public NumberInterface applyInternal(MutableEvaluationContext context, NumberInterface[] params) {
-            return functionSin.apply(context, piFor(params[0].getClass()).divide(context.getInheritedNumberImplementation().instanceForString("2"))
-                    .subtract(params[0]));
-        }
-    };
-    /**
-     * The tangent function (the argument is in radians).
-     */
-    public final NumberFunction functionTan = new NumberFunction() {
-        @Override
-        public boolean matchesParams(MutableEvaluationContext context, NumberInterface[] params) {
-            return params.length == 1;
-        }
-
-        @Override
-        public NumberInterface applyInternal(MutableEvaluationContext context, NumberInterface[] params) {
-            return functionSin.apply(context, params[0]).divide(functionCos.apply(context, params[0]));
-        }
-    };
-    /**
-     * The secant function (the argument is in radians).
-     */
-    public final NumberFunction functionSec = new NumberFunction() {
-        @Override
-        public boolean matchesParams(MutableEvaluationContext context, NumberInterface[] params) {
-            return params.length == 1;
-        }
-
-        @Override
-        public NumberInterface applyInternal(MutableEvaluationContext context, NumberInterface[] params) {
-            return context.getInheritedNumberImplementation().instanceForString("1").divide(functionCos.apply(context, params[0]));
-        }
-    };
-    /**
-     * The cosecant function (the argument is in radians).
-     */
-    public final NumberFunction functionCsc = new NumberFunction() {
-        @Override
-        public boolean matchesParams(MutableEvaluationContext context, NumberInterface[] params) {
-            return params.length == 1;
-        }
-
-        @Override
-        public NumberInterface applyInternal(MutableEvaluationContext context, NumberInterface[] params) {
-            return context.getInheritedNumberImplementation().instanceForString("1").divide(functionSin.apply(context, params[0]));
-        }
-    };
-    /**
-     * The cotangent function (the argument is in radians).
-     */
-    public final NumberFunction functionCot = new NumberFunction() {
-        @Override
-        public boolean matchesParams(MutableEvaluationContext context, NumberInterface[] params) {
-            return params.length == 1;
-        }
-
-        @Override
-        public NumberInterface applyInternal(MutableEvaluationContext context, NumberInterface[] params) {
-            return functionCos.apply(context, params[0]).divide(functionSin.apply(context, params[0]));
-        }
-    };
-
-    /**
-     * The arcsine function (return type in radians).
-     */
-    public final NumberFunction functionArcsin = new NumberFunction() {
-        @Override
-        public boolean matchesParams(MutableEvaluationContext context, NumberInterface[] params) {
-            return params.length == 1
-                    && FUNCTION_ABS.apply(context, params[0]).compareTo(context.getInheritedNumberImplementation().instanceForString("1")) <= 0;
-        }
-
-        @Override
-        public NumberInterface applyInternal(MutableEvaluationContext context, NumberInterface[] params) {
-            NumberImplementation implementation = context.getInheritedNumberImplementation();
-            if (FUNCTION_ABS.apply(context, params[0]).compareTo(implementation.instanceForString(".8")) >= 0) {
-                NumberInterface[] newParams = {FUNCTION_SQRT.apply(context, implementation.instanceForString("1").subtract(params[0].multiply(params[0])))};
-                return piFor(params[0].getClass()).divide(implementation.instanceForString("2"))
-                        .subtract(applyInternal(context, newParams)).multiply(implementation.instanceForString(Integer.toString(params[0].signum())));
-            }
-            NumberInterface currentTerm = params[0], sum = currentTerm,
-                    multiplier = currentTerm.multiply(currentTerm), summandBound = sum.getMaxError().multiply(implementation.instanceForString("1").subtract(multiplier)),
-                    power = currentTerm, coefficient = implementation.instanceForString("1");
-            int exponent = 1;
-            while (FUNCTION_ABS.apply(context, currentTerm).compareTo(summandBound) > 0) {
-                exponent += 2;
-                power = power.multiply(multiplier);
-                coefficient = coefficient.multiply(implementation.instanceForString(Integer.toString(exponent - 2)))
-                        .divide(implementation.instanceForString(Integer.toString(exponent - 1)));
-                currentTerm = power.multiply(coefficient).divide(implementation.instanceForString(Integer.toString(exponent)));
-                sum = sum.add(currentTerm);
-            }
-            return sum;
-        }
-    };
-
-    /**
-     * The arccosine function.
-     */
-    public final NumberFunction functionArccos = new NumberFunction() {
-        @Override
-        public boolean matchesParams(MutableEvaluationContext context, NumberInterface[] params) {
-            return params.length == 1 && FUNCTION_ABS.apply(context, params[0]).compareTo(context.getInheritedNumberImplementation().instanceForString("1")) <= 0;
-        }
-
-        @Override
-        public NumberInterface applyInternal(MutableEvaluationContext context, NumberInterface[] params) {
-            return piFor(params[0].getClass()).divide(context.getInheritedNumberImplementation().instanceForString("2"))
-                    .subtract(functionArcsin.apply(context, params));
-        }
-    };
-
-    /**
-     * The arccosecant function.
-     */
-    public final NumberFunction functionArccsc = new NumberFunction() {
-        @Override
-        public boolean matchesParams(MutableEvaluationContext context, NumberInterface[] params) {
-            return params.length == 1 && FUNCTION_ABS.apply(context, params[0]).compareTo(context.getInheritedNumberImplementation().instanceForString("1")) >= 0;
-        }
-
-        @Override
-        public NumberInterface applyInternal(MutableEvaluationContext context, NumberInterface[] params) {
-            NumberInterface[] reciprocalParamArr = {context.getInheritedNumberImplementation().instanceForString("1").divide(params[0])};
-            return functionArcsin.apply(context, reciprocalParamArr);
-        }
-    };
-
-    /**
-     * The arcsecant function.
-     */
-    public final NumberFunction functionArcsec = new NumberFunction() {
-        @Override
-        public boolean matchesParams(MutableEvaluationContext context, NumberInterface[] params) {
-            return params.length == 1 && FUNCTION_ABS.apply(context, params[0]).compareTo(context.getInheritedNumberImplementation().instanceForString("1")) >= 0;
-        }
-
-        @Override
-        public NumberInterface applyInternal(MutableEvaluationContext context, NumberInterface[] params) {
-            NumberInterface[] reciprocalParamArr = {context.getInheritedNumberImplementation().instanceForString("1").divide(params[0])};
-            return functionArccos.apply(context, reciprocalParamArr);
-        }
-    };
-
-    /**
-     * The arctangent function.
-     */
-    public final NumberFunction functionArctan = new NumberFunction() {
-        @Override
-        public boolean matchesParams(MutableEvaluationContext context, NumberInterface[] params) {
-            return params.length == 1;
-        }
-
-        @Override
-        public NumberInterface applyInternal(MutableEvaluationContext context, NumberInterface[] params) {
-            NumberImplementation implementation = context.getInheritedNumberImplementation();
-            if (params[0].signum() == -1) {
-                NumberInterface[] negatedParams = {params[0].negate()};
-                return applyInternal(context, negatedParams).negate();
-            }
-            if (params[0].compareTo(implementation.instanceForString("1")) > 0) {
-                NumberInterface[] reciprocalParams = {implementation.instanceForString("1").divide(params[0])};
-                return piFor(params[0].getClass()).divide(implementation.instanceForString("2"))
-                        .subtract(applyInternal(context, reciprocalParams));
-            }
-            if (params[0].compareTo(implementation.instanceForString("1")) == 0) {
-                return piFor(params[0].getClass()).divide(implementation.instanceForString("4"));
-            }
-            if (params[0].compareTo(implementation.instanceForString(".9")) >= 0) {
-                NumberInterface[] newParams = {params[0].multiply(implementation.instanceForString("2"))
-                        .divide(implementation.instanceForString("1").subtract(params[0].multiply(params[0])))};
-                return applyInternal(context, newParams).divide(implementation.instanceForString("2"));
-            }
-            NumberInterface currentPower = params[0], currentTerm = currentPower, sum = currentTerm,
-                    maxError = params[0].getMaxError(), multiplier = currentPower.multiply(currentPower).negate();
-            int n = 1;
-            while (FUNCTION_ABS.apply(context, currentTerm).compareTo(maxError) > 0) {
-                n += 2;
-                currentPower = currentPower.multiply(multiplier);
-                currentTerm = currentPower.divide(implementation.instanceForString(Integer.toString(n)));
-                sum = sum.add(currentTerm);
-            }
-            return sum;
-        }
-    };
-
-    /**
-     * The arccotangent function. Range: (0, pi).
-     */
-    public final NumberFunction functionArccot = new NumberFunction() {
-        @Override
-        public boolean matchesParams(MutableEvaluationContext context, NumberInterface[] params) {
-            return params.length == 1;
-        }
-
-        @Override
-        public NumberInterface applyInternal(MutableEvaluationContext context, NumberInterface[] params) {
-            return piFor(params[0].getClass()).divide(context.getInheritedNumberImplementation().instanceForString("2"))
-                    .subtract(functionArctan.apply(context, params));
-        }
-    };
-
-    public StandardPlugin(PluginManager manager) {
-        super(manager);
-    }
-
-    /**
-     * A factorial function that uses memoization for each number class; it efficiently
-     * computes factorials of non-negative integers.
-     *
-     * @param implementation type of number to return.
-     * @param n              non-negative integer.
-     * @return a number of numClass with value n factorial.
-     */
-    synchronized public static NumberInterface factorial(NumberImplementation implementation, int n) {
-        if (!FACTORIAL_LISTS.containsKey(implementation)) {
-            FACTORIAL_LISTS.put(implementation, new ArrayList<>());
-            FACTORIAL_LISTS.get(implementation).add(implementation.instanceForString("1"));
-            FACTORIAL_LISTS.get(implementation).add(implementation.instanceForString("1"));
-        }
-        ArrayList<NumberInterface> list = FACTORIAL_LISTS.get(implementation);
-        if (n >= list.size()) {
-            while (list.size() < n + 16) {
-                list.add(list.get(list.size() - 1).multiply(implementation.instanceForString(Integer.toString(list.size()))));
-            }
-        }
-        return list.get(n);
-    }
-
-    /**
-     * Returns the value of the Taylor series for sin (centered at 0) at x.
-     *
-     * @param x where the series is evaluated.
-     * @return the value of the series
-     */
-    private static NumberInterface sinTaylor(MutableEvaluationContext context, NumberInterface x) {
-        NumberInterface power = x, multiplier = x.multiply(x).negate(), currentTerm = x, sum = x;
-        NumberInterface maxError = x.getMaxError();
-        int n = 1;
-        do {
-            n += 2;
-            power = power.multiply(multiplier);
-            currentTerm = power.divide(factorial(context.getInheritedNumberImplementation(), n));
-            sum = sum.add(currentTerm);
-        } while (FUNCTION_ABS.apply(context, currentTerm).compareTo(maxError) > 0);
-        return sum;
-    }
-
-    /**
-     * Returns an equivalent angle in the interval [0, 2pi)
-     *
-     * @param phi an angle (in radians).
-     * @return theta in [0, 2pi) that differs from phi by a multiple of 2pi.
-     */
-    private static NumberInterface getSmallAngle(MutableEvaluationContext context, NumberInterface phi, NumberInterface pi) {
-        NumberInterface twoPi = pi.multiply(context.getInheritedNumberImplementation().instanceForString("2"));
-        NumberInterface theta = FUNCTION_ABS.apply(context, phi).subtract(twoPi
-                .multiply(FUNCTION_ABS.apply(context, phi).divide(twoPi).floor())); //Now theta is in [0, 2pi).
-        if (phi.signum() < 0) {
-            theta = twoPi.subtract(theta);
-        }
-        return theta;
-    }
-
-    @Override
-    public void onEnable() {
-        registerNumberImplementation("naive", IMPLEMENTATION_NAIVE);
-        registerNumberImplementation("precise", IMPLEMENTATION_PRECISE);
-
-        registerOperator("+", OP_ADD);
-        registerOperator("-", OP_SUBTRACT);
-        registerOperator("`", OP_NEGATE);
-        registerOperator("*", OP_MULTIPLY);
-        registerOperator("/", OP_DIVIDE);
-        registerOperator("^", OP_CARET);
-        registerOperator("!", OP_FACTORIAL);
-
-        registerTreeValueOperator("=", opSet);
-        registerTreeValueOperator(":=", opDefine);
-
-        registerOperator("nPr", OP_NPR);
-        registerOperator("nCr", OP_NCR);
-
-        registerFunction("abs", FUNCTION_ABS);
-        registerFunction("exp", FUNCTION_EXP);
-        registerFunction("ln", FUNCTION_LN);
-        registerFunction("sqrt", FUNCTION_SQRT);
-
-        registerFunction("sin", functionSin);
-        registerFunction("cos", functionCos);
-        registerFunction("tan", functionTan);
-        registerFunction("sec", functionSec);
-        registerFunction("csc", functionCsc);
-        registerFunction("cot", functionCot);
-
-        registerFunction("arcsin", functionArcsin);
-        registerFunction("arccos", functionArccos);
-        registerFunction("arctan", functionArctan);
-        registerFunction("arcsec", functionArcsec);
-        registerFunction("arccsc", functionArccsc);
-        registerFunction("arccot", functionArccot);
-
-        registerFunction("random_int", FUNCTION_RAND_INT);
-
-        registerDocumentation(new Documentation("abs", "Absolute Value", "Finds the distance " +
-                "from zero of a number.", "Given a number, this function finds the distance form " +
-                "zero of a number, effectively turning negative numbers into positive ones.\n\n" +
-                "Example: abs(-2) -> 2", DocumentationType.FUNCTION));
-        registerDocumentation(new Documentation("exp", "Exponentiate", "Brings e to the given power.",
-                "This function evaluates e to the power of the given value, and is the inverse " +
-                        "of the natural logarithm.\n\n" +
-                        "Example: exp(1) -> 2.718...", DocumentationType.FUNCTION));
-        registerDocumentation(new Documentation("ln", "Natural Logarithm", "Gets the natural " +
-                "logarithm of the given value.", "The natural logarithm of a number is " +
-                "the power that e has to be brought to to be equal to the number.\n\n" +
-                "Example: ln(2.718) -> 1", DocumentationType.FUNCTION));
-        registerDocumentation(new Documentation("sqrt", "Square Root", "Finds the square root " +
-                "of the number.", "A square root a of a number is defined as the non-negative a such that a times a is equal " +
-                "to that number.\n\n" +
-                "Example: sqrt(4) -> 2", DocumentationType.FUNCTION));
-        registerDocumentation(new Documentation("sin", "Sine", "Computes the sine of the given angle, " +
-                "in radians.", "Example: sin(pi/6) -> 0.5", DocumentationType.FUNCTION));
-        registerDocumentation(new Documentation("cos", "Cosine", "Computes the cosine of the given angle, " +
-                "in radians.", "Example: cos(pi/6) -> 0.866... (the exact result is sqrt(3)/2)", DocumentationType.FUNCTION));
-        registerDocumentation(new Documentation("tan", "Tangent", "Computes the tangent of the given angle, " +
-                "in radians.", "Example: tan(pi/6) -> 0.577... (the exact result is 1/sqrt(3))", DocumentationType.FUNCTION));
-        registerDocumentation(new Documentation("sec", "Secant", "Computes the secant of the given angle, " +
-                "in radians.", "Example: sec(pi/6) -> 1.154... (the exact result is 2/sqrt(3))", DocumentationType.FUNCTION));
-        registerDocumentation(new Documentation("csc", "Cosecant", "Computes the cosecant of the given angle, " +
-                "in radians.", "Example: csc(pi/6) -> 2", DocumentationType.FUNCTION));
-        registerDocumentation(new Documentation("cot", "Cotangent", "Computes the cotangent of the given angle, " +
-                "in radians.", "Example: cot(pi/6) -> 1.732... (the exact result is sqrt(3))", DocumentationType.FUNCTION));
-        registerDocumentation(new Documentation("random_int", "Random Integer", "Generates a random integer [0, n].",
-                "Generates a pseudorandom number using the standard JVM random mechanism, keeping it less than or " +
-                        "equal to the given number.\n\n" +
-                        "Example: random_int(5) -> 4\n" +
-                        "random_int(5) -> 3\n" +
-                        "random_int(5) -> 3\n", DocumentationType.FUNCTION));
-        registerDocumentation(new Documentation("arcsin", "Arcsine", "Computes the arcsine of x. (The result is in radians.)",
-                "Example: arcsin(0.5) -> 0.523... (the exact result is pi/6)", DocumentationType.FUNCTION));
-        registerDocumentation(new Documentation("arccos", "Arccosine", "Computes the arccosine of x. (The result is in radians.)",
-                "Example: arccos(0.5) -> 1.047... (the exact result is pi/3)", DocumentationType.FUNCTION));
-        registerDocumentation(new Documentation("arctan", "Arctangent", "Computes the arctangent of x. (The result is in radians.)",
-                "Example: arctan(1) -> 0.785... (the exact result is pi/4)", DocumentationType.FUNCTION));
-        registerDocumentation(new Documentation("arcsec", "Arcsecant", "Computes the arcsecant of x. (The result is in radians.)",
-                "Example: arcsec(2) -> 1.047... (the exact result is pi/3)", DocumentationType.FUNCTION));
-        registerDocumentation(new Documentation("arccsc", "Arccosecant", "Computes the arcscosecant of x. (The result is in radians.)",
-                "Example: arccsc(2) -> 0.523... (the exact result is pi/6)", DocumentationType.FUNCTION));
-        registerDocumentation(new Documentation("arccot", "Arccotangent", "Computes the arccotangent of x. (The result is in radians," +
-                " in the range (0, pi).)",
-                "Example: arccot(0) -> 1.570... (the exact result is pi/2)", DocumentationType.FUNCTION));
-    }
-
-    @Override
-    public void onDisable() {
-        FACTORIAL_LISTS.clear();
-    }
-}

core/src/main/kotlin/org/nwapw/abacus/Abacus.kt

@@ -1,115 +0,0 @@
-package org.nwapw.abacus
-
-import org.nwapw.abacus.config.Configuration
-import org.nwapw.abacus.context.MutableEvaluationContext
-import org.nwapw.abacus.context.EvaluationContext
-import org.nwapw.abacus.number.PromotionManager
-import org.nwapw.abacus.parsing.LexerTokenizer
-import org.nwapw.abacus.parsing.ShuntingYardParser
-import org.nwapw.abacus.parsing.TreeBuilder
-import org.nwapw.abacus.plugin.PluginManager
-import org.nwapw.abacus.plugin.StandardPlugin
-import org.nwapw.abacus.tree.EvaluationResult
-import org.nwapw.abacus.tree.NumberReducer
-import org.nwapw.abacus.tree.TreeNode
-
-/**
- * Core class to handle all mathematics.
- *
- * The main calculator class. This is responsible
- * for piecing together all of the components, allowing
- * their interaction with each other.
- *
- * @property configuration the configuration to use.
- */
-class Abacus(val configuration: Configuration) {
-
-    /**
-     * The tokenizer used to convert strings into tokens.
-     */
-    private val tokenizer = LexerTokenizer()
-    /**
-     * Parser the parser used to convert tokens into trees.
-     */
-    private val parser = ShuntingYardParser()
-    /**
-     * The plugin manager used to handle loading and unloading plugins.
-     */
-    val pluginManager = PluginManager(this)
-    /**
-     * The tree builder that handles the conversion of strings into trees.
-     */
-    val treeBuilder = TreeBuilder(tokenizer, parser)
-    /**
-     * The promotion manager used to convert between number implementations.
-     */
-    val promotionManager = PromotionManager(this)
-
-    /**
-     * The hidden, mutable implementation of the context.
-     */
-    private val mutableContext = MutableEvaluationContext(numberImplementation = StandardPlugin.IMPLEMENTATION_NAIVE)
-    /**
-     * The base context from which calculations are started.
-     */
-    val context: EvaluationContext
-        get() = mutableContext
-
-    init {
-        pluginManager.addListener(tokenizer)
-        pluginManager.addListener(parser)
-        pluginManager.addListener(promotionManager)
-    }
-
-    /**
-     * Reloads the Abacus core.
-     */
-    fun reload(){
-        pluginManager.reload()
-        with(mutableContext) {
-            numberImplementation = pluginManager.numberImplementationFor(configuration.numberImplementation)
-                    ?: StandardPlugin.IMPLEMENTATION_NAIVE
-            clearVariables()
-            clearDefinitions()
-        }
-    }
-    /**
-     * Merges the current context with the provided one, updating
-     * variables and the like.
-     * @param context the context to apply.
-     */
-    fun applyToContext(context: EvaluationContext){
-        mutableContext.apply(context)
-    }
-    /**
-     * Parses a string into a tree structure using the main
-     * tree builder.
-     *
-     * @param input the input string to parse
-     * @return the resulting tree, null if the tree builder or the produced tree are null.
-     */
-    fun parseString(input: String): TreeNode? = treeBuilder.fromString(input)
-    /**
-     * Evaluates the given tree.
-     *
-     * @param tree the tree to reduce, must not be null.
-     * @return the evaluation result.
-     */
-    fun evaluateTree(tree: TreeNode): EvaluationResult {
-        return evaluateTreeWithContext(tree, context.mutableSubInstance())
-    }
-    /**
-     * Evaluates the given tree using a different context than
-     * the default one.
-     *
-     * @param tree the tree to reduce, must not be null.
-     * @param context the context to use for the evaluation.
-     * @return the evaluation result.
-     */
-    fun evaluateTreeWithContext(tree: TreeNode, context: MutableEvaluationContext): EvaluationResult {
-        val newReducer = NumberReducer(this, context)
-        val evaluationValue = tree.reduce(newReducer)
-        return EvaluationResult(evaluationValue, newReducer.context)
-    }
-
-}

core/src/main/kotlin/org/nwapw/abacus/config/Configuration.kt

@@ -1,20 +0,0 @@
-package org.nwapw.abacus.config
-
-/**
- * A class that holds information that tells Abacus how to behave.
- *
- * Configuration stores information about how Abacus should behave, for
- * instance, what number implementation it should use and what
- * plugins should be ignored during loading.
- *
- * @property numberImplementation the number implementation Abacus should use for loading.
- * @param disabledPlugins the plugins that should be disabled and not loaded by the plugin manager.
- */
-open class Configuration(var numberImplementation: String = "<default>", disabledPlugins: Array<String> = emptyArray()) {
-
-    /**
-     * The set of disabled plugins that should be ignored by the plugin manager.
-     */
-    val disabledPlugins = disabledPlugins.toMutableSet()
-
-}

core/src/main/kotlin/org/nwapw/abacus/context/ChainAccumulateDelegate.kt

@@ -1,26 +0,0 @@
-package org.nwapw.abacus.context
-
-import kotlin.reflect.KProperty
-
-/**
- * A delegate to accumulate a collection of elements in a [EvaluationContext] hierarchy.
- *
- * ChainAccumulateDelegate is similar to the [ChainSearchDelegate], however, it operates only on collections.
- * Instead of returning the most recent collection, it merges them into a [Set].
- *
- * @param T the type of element in the collection.
- * @property valueGetter the getter used to access the collection from the context.
- */
-class ChainAccumulateDelegate<out T>(private val valueGetter: EvaluationContext.() -> Collection<T>) {
-
-    operator fun getValue(selfRef: Any, property: KProperty<*>): Set<T> {
-        val set = mutableSetOf<T>()
-        var currentRef: EvaluationContext = selfRef as? EvaluationContext ?: return set
-        while(true) {
-            set.addAll(currentRef.valueGetter())
-            currentRef = currentRef.parent ?: break
-        }
-        return set
-    }
-
-}

core/src/main/kotlin/org/nwapw/abacus/context/ChainSearchDelegate.kt

@@ -1,29 +0,0 @@
-package org.nwapw.abacus.context
-
-import kotlin.reflect.KProperty
-
-/**
- * A delegate to search a hierarchy made up of [EvaluationContext].
- *
- * ChainSearchDelegate is a variable delegate written specifically for use in [EvaluationContext], because
- * of its hierarchical structure. Variables not found in the current context are searched
- * for in its parent, which continues recursively until the context being examined has no parent.
- * This class assists that logic, which is commonly re-used with different variable types, by calling
- * [valueGetter] on the current context, then its parent, etc.
- *
- * @param V the type of the property to search recursively.
- * @property valueGetter the getter lambda to access the value from the context.
- */
-class ChainSearchDelegate<out V>(private val valueGetter: EvaluationContext.() -> V?) {
-
-    operator fun getValue(selfRef: Any, property: KProperty<*>): V? {
-        var currentRef = selfRef as? EvaluationContext ?: return null
-        var returnedValue = currentRef.valueGetter()
-        while (returnedValue == null) {
-            currentRef = currentRef.parent ?: break
-            returnedValue = currentRef.valueGetter()
-        }
-        return returnedValue
-    }
-
-}

core/src/main/kotlin/org/nwapw/abacus/context/EvaluationContext.kt

@@ -1,84 +0,0 @@
-package org.nwapw.abacus.context
-
-import org.nwapw.abacus.number.NumberInterface
-import org.nwapw.abacus.plugin.NumberImplementation
-import org.nwapw.abacus.tree.Reducer
-import org.nwapw.abacus.tree.TreeNode
-
-/**
- * A context for the reduction of a [org.nwapw.abacus.tree.TreeNode] into a number.
- *
- * The reduction context is used to carry important state information captured at the beginning
- * of the reduction of an expression, such as the variables and the implementation in use.
- *
- * @property parent the parent of this context.
- * @property numberImplementation the implementation for numbers of this context.
- * @property reducer the reducer used by this context.
- */
-open class EvaluationContext(val parent: EvaluationContext? = null,
-                             open val numberImplementation: NumberImplementation? = null,
-                             open val reducer: Reducer<NumberInterface>? = null) {
-
-    /**
-     * The map of variables in this context.
-     */
-    protected val variableMap = mutableMapOf<String, NumberInterface>()
-    /**
-     * The map of definitions in this context.
-     */
-    protected val definitionMap = mutableMapOf<String, TreeNode>()
-
-    /**
-     * The set of all variable names defined in this context.
-     */
-    val variables: Set<String>
-        get() = variableMap.keys
-
-    /**
-     * The set of all definition names defined in this context.
-     */
-    val definitions: Set<String>
-        get() = definitionMap.keys
-
-    /**
-     * The implementation inherited from this context's parent.
-     */
-    val inheritedNumberImplementation: NumberImplementation?
-            by ChainSearchDelegate { numberImplementation}
-
-    /**
-     * The reducer inherited from this context's parent.
-     */
-    val inheritedReducer: Reducer<NumberInterface>?
-            by ChainSearchDelegate { reducer }
-
-    /**
-     * The set of all variables in this context and its parents.
-     */
-    val inheritedVariables: Set<String> by ChainAccumulateDelegate { variables }
-
-    /**
-     * The set of all definition in this context and its parents.
-     */
-    val inheritedDefinitions: Set<String> by ChainAccumulateDelegate { definitions }
-
-    /**
-     * Create a new child instance of this context that is mutable.
-     * @return the new child instance.
-     */
-    fun mutableSubInstance(): MutableEvaluationContext = MutableEvaluationContext(this)
-
-    /**
-     * Gets a variable stored in this context.
-     */
-    fun getVariable(name: String): NumberInterface? {
-        return variableMap[name] ?: parent?.getVariable(name)
-    }
-    /**
-     * Gets the definition stored in this context.
-     */
-    fun getDefinition(name: String): TreeNode? {
-        return definitionMap[name] ?: parent?.getDefinition(name)
-    }
-
-}

core/src/main/kotlin/org/nwapw/abacus/context/MutableEvaluationContext.kt

@@ -1,69 +0,0 @@
-package org.nwapw.abacus.context
-
-import org.nwapw.abacus.number.NumberInterface
-import org.nwapw.abacus.plugin.NumberImplementation
-import org.nwapw.abacus.tree.Reducer
-import org.nwapw.abacus.tree.TreeNode
-
-/**
- * A reduction context that is mutable.
- * @param parent the parent of this context.
- * @param numberImplementation the number implementation used in this context.
- * @param reducer the reducer used in this context
- */
-class MutableEvaluationContext(parent: EvaluationContext? = null,
-                               numberImplementation: NumberImplementation? = null,
-                               reducer: Reducer<NumberInterface>? = null) :
-        EvaluationContext(parent, numberImplementation, reducer) {
-
-    override var numberImplementation: NumberImplementation? = super.numberImplementation
-    override var reducer: Reducer<NumberInterface>? = super.reducer
-
-    /**
-     * Writes data stored in the [other] context over data stored in this one.
-     * @param other the context from which to copy data.
-     */
-    fun apply(other: EvaluationContext) {
-        if(other.numberImplementation != null) numberImplementation = other.numberImplementation
-        if(other.reducer != null) reducer = other.reducer
-        for(name in other.variables) {
-            setVariable(name, other.getVariable(name) ?: continue)
-        }
-        for(name in other.definitions) {
-            setDefinition(name, other.getDefinition(name) ?: continue)
-        }
-    }
-
-    /**
-     * Sets a variable to a certain [value].
-     * @param name the name of the variable.
-     * @param value the value of the variable.
-     */
-    fun setVariable(name: String, value: NumberInterface) {
-        variableMap[name] = value
-    }
-
-    /**
-     * Set a definition to a certain [value].
-     * @param name the name of the definition.
-     * @param value the value of the definition.
-     */
-    fun setDefinition(name: String, value: TreeNode) {
-        definitionMap[name] = value
-    }
-
-    /**
-     * Clears the variables defined in this context.
-     */
-    fun clearVariables(){
-        variableMap.clear()
-    }
-
-    /**
-     * Clears the definitions defined in this context.
-     */
-    fun clearDefinitions(){
-        definitionMap.clear()
-    }
-
-}

core/src/main/kotlin/org/nwapw/abacus/function/Documentation.kt

@@ -1,26 +0,0 @@
-package org.nwapw.abacus.function
-
-/**
- * A data class used for storing information about a function.
- *
- * The Documentation class holds the information necessary to display the information
- * about a function to the user.
- *
- * @param codeName the name of the function as it occurs in code.
- * @param name the name of the function in English.
- * @param description the short description of this function.
- * @param longDescription the full description of this function.
- * @param type the things this documentation maps to.
- */
-data class Documentation(val codeName: String, val name: String,
-                         val description: String, val longDescription: String,
-                         val type: DocumentationType) {
-
-    fun matches(other: String): Boolean {
-        return codeName.toLowerCase().contains(other.toLowerCase()) ||
-                name.toLowerCase().contains(other.toLowerCase()) ||
-                description.toLowerCase().contains(other.toLowerCase()) ||
-                longDescription.toLowerCase().contains(other.toLowerCase())
-    }
-
-}

core/src/main/kotlin/org/nwapw/abacus/function/NumberFunction.kt

@@ -1,12 +0,0 @@
-package org.nwapw.abacus.function
-
-import org.nwapw.abacus.function.applicable.Applicable
-import org.nwapw.abacus.number.NumberInterface
-
-/**
- * A function that operates on numbers.
- *
- * This function takes some number of input NumberInterfaces and returns
- * another NumberInterface as a result.
- */
-abstract class NumberFunction : Applicable<NumberInterface, NumberInterface>

core/src/main/kotlin/org/nwapw/abacus/function/NumberOperator.kt

@@ -1,17 +0,0 @@
-package org.nwapw.abacus.function
-
-import org.nwapw.abacus.function.applicable.Applicable
-import org.nwapw.abacus.number.NumberInterface
-
-/**
- * An operator that operates on NumberImplementations.
- *
- * This is simply an alias for Operator<NumberInterface, NumberInterface>.
- * @param associativity the associativity of the operator.
- * @param type the type of the operator (binary, unary, etc)
- * @param precedence the precedence of the operator.
- */
-abstract class NumberOperator(associativity: OperatorAssociativity, type: OperatorType,
-                              precedence: Int) :
-        Operator(associativity, type, precedence),
-        Applicable<NumberInterface, NumberInterface>

core/src/main/kotlin/org/nwapw/abacus/function/TreeValueFunction.kt

@@ -1,13 +0,0 @@
-package org.nwapw.abacus.function
-
-import org.nwapw.abacus.function.applicable.Applicable
-import org.nwapw.abacus.number.NumberInterface
-import org.nwapw.abacus.tree.TreeNode
-
-/**
- * A function that operates on trees.
- *
- * A function that operates on parse tree nodes instead of on already simplified numbers.
- * Despite this, it returns a number, not a tree.
- */
-abstract class TreeValueFunction : Applicable<TreeNode, NumberInterface>

core/src/main/kotlin/org/nwapw/abacus/function/TreeValueOperator.kt

@@ -1,18 +0,0 @@
-package org.nwapw.abacus.function
-
-import org.nwapw.abacus.function.applicable.Applicable
-import org.nwapw.abacus.number.NumberInterface
-import org.nwapw.abacus.tree.TreeNode
-
-/**
- * An operator that operates on trees.
- *
- * This operator operates on parse trees, returning, however a number.
- * @param associativity the associativity of the operator.
- * @param type the type of the operator (infix, postfix, etc)
- * @param precedence the precedence of the operator.
- */
-abstract class TreeValueOperator(associativity: OperatorAssociativity, type: OperatorType,
-                                 precedence: Int) :
-        Operator(associativity, type, precedence),
-        Applicable<TreeNode, NumberInterface>

core/src/main/kotlin/org/nwapw/abacus/function/applicable/Applicable.kt

@@ -1,44 +0,0 @@
-package org.nwapw.abacus.function.applicable
-
-import org.nwapw.abacus.context.MutableEvaluationContext
-import org.nwapw.abacus.exception.DomainException
-
-/**
- * A class that can be applied to arguments.
- *
- * Applicable is a class that represents something that can be applied to one or more
- * arguments of the same type, and returns a single value from that application.
- * @param <T> the type of the parameters passed to this applicable.
- * @param <O> the return type of the applicable.
- */
-interface Applicable<in T : Any, out O : Any> {
-
-    /**
-     * Checks if the given applicable can be used with the given parameters.
-     * @param params the parameter array to verify for compatibility.
-     * @return whether the array can be used with applyInternal.
-     */
-    fun matchesParams(context: MutableEvaluationContext, params: Array<out T>): Boolean
-
-    /**
-     * Applies the applicable object to the given parameters,
-     * without checking for compatibility.
-     * @param params the parameters to apply to.
-     * @return the result of the application.
-     */
-    fun applyInternal(context: MutableEvaluationContext, params: Array<out T>): O
-
-    /**
-     * If the parameters can be used with this applicable, returns
-     * the result of the application of the applicable to the parameters.
-     * Otherwise, returns null.
-     * @param params the parameters to apply to.
-     * @return the result of the operation, or null if parameters do not match.
-     */
-    fun apply(context: MutableEvaluationContext, vararg params: T): O {
-        if (!matchesParams(context, params))
-            throw DomainException("parameters do not match function requirements.")
-        return applyInternal(context, params)
-    }
-
-}

core/src/main/kotlin/org/nwapw/abacus/number/NumberUtils.kt

@@ -1,16 +0,0 @@
-@file:JvmName("NumberUtils")
-package org.nwapw.abacus.number
-
-typealias PromotionFunction = java.util.function.Function<NumberInterface, NumberInterface>
-typealias PromotionPath = List<PromotionFunction>
-typealias NumberClass = Class<NumberInterface>
-
-/**
- * Promote a number through this path. The functions in this path
- * are applied in order to the number, and the final result is returned.
- *
- * @param from the number to start from.
- */
-fun PromotionPath.promote(from: NumberInterface): NumberInterface {
-    return fold(from, { current, function -> function.apply(current) })
-}

core/src/main/kotlin/org/nwapw/abacus/number/PromotionManager.kt

@@ -1,78 +0,0 @@
-package org.nwapw.abacus.number
-
-import org.nwapw.abacus.Abacus
-import org.nwapw.abacus.plugin.NumberImplementation
-import org.nwapw.abacus.plugin.PluginListener
-import org.nwapw.abacus.plugin.PluginManager
-import java.util.function.Function
-
-/**
- * A class that handles promotions based on priority and the
- * transition paths each implementation provides.
- *
- * @property abacus the Abacus instance to use to access other components.
- */
-class PromotionManager(val abacus: Abacus) : PluginListener {
-
-    /**
-     * The already computed paths
-     */
-    val computePaths = mutableMapOf<Pair<NumberImplementation, NumberImplementation>, PromotionPath?>()
-
-    /**
-     * Computes a path between a starting and an ending implementation.
-     *
-     * @param from the implementation to start from.
-     * @param to the implementation to get to.
-     * @return the resulting promotion path, or null if it is not found
-     */
-    fun computePathBetween(from: NumberImplementation, to: NumberImplementation): PromotionPath? {
-        val fromName = abacus.pluginManager.interfaceImplementationNameFor(from.implementation)
-        val toName = abacus.pluginManager.interfaceImplementationNameFor(to.implementation)
-
-        if(fromName == toName) return listOf(Function { it })
-
-        if(from.promotionPaths.containsKey(toName))
-            return listOf(from.promotionPaths[toName] ?: return null)
-        return null
-    }
-
-    /**
-     * Promote all the numbers in the list to the same number implementation, to ensure
-     * they can be used with each other. Finds the highest priority implementation
-     * in the list, and promotes all other numbers to it.
-     *
-     * @param numbers the numbers to promote.
-     * @return the resulting promotion result.
-     */
-    fun promote(vararg numbers: NumberInterface): PromotionResult? {
-        val pluginManager = abacus.pluginManager
-        val implementations = numbers.map { pluginManager.interfaceImplementationFor(it.javaClass) }
-        val highestPriority = implementations.sortedBy { it.priority }.last()
-        return PromotionResult(items = numbers.map {
-            if(it.javaClass == highestPriority.implementation) it
-            else computePaths[pluginManager.interfaceImplementationFor(it.javaClass) to highestPriority]
-                    ?.promote(it) ?: return null
-        }.toTypedArray(), promotedTo = highestPriority)
-    }
-
-    override fun onLoad(manager: PluginManager) {
-        val implementations = manager.allNumberImplementations.map { manager.numberImplementationFor(it) }
-        for((index, value) in implementations.withIndex()){
-            for(i in index until implementations.size){
-                val other = implementations[i]
-
-                val promoteFrom = if(other.priority > value.priority) value else other
-                val promoteTo = if(other.priority > value.priority) other else value
-                val path = computePathBetween(promoteFrom, promoteTo)
-                computePaths.put(promoteFrom to promoteTo, path)
-            }
-        }
-    }
-
-    override fun onUnload(manager: PluginManager) {
-        computePaths.clear()
-    }
-
-
-}

core/src/main/kotlin/org/nwapw/abacus/number/PromotionResult.kt

@@ -1,11 +0,0 @@
-package org.nwapw.abacus.number
-
-import org.nwapw.abacus.plugin.NumberImplementation
-
-/**
- * The result of promoting an array of NumberInterfaces.
- *
- * @param promotedTo the implementation to which the numbers were promoted.
- * @param items the items the items resulting from the promotion.
- */
-data class PromotionResult(val promotedTo: NumberImplementation, val items: Array<NumberInterface>)

core/src/main/kotlin/org/nwapw/abacus/tree/CallNode.kt

@@ -1,25 +0,0 @@
-package org.nwapw.abacus.tree
-
-/**
- * Represents a more generic function call.
- *
- * This class does not specify how it should be reduced, allowing other classes
- * to extend this functionality.
- *
- * @param callTo the name of the things being called.
- * @param children the children of this node.
- */
-abstract class CallNode(val callTo: String, val children: List<TreeNode>) : TreeNode() {
-
-    override fun toString(): String {
-        val buffer = StringBuffer()
-        buffer.append(callTo)
-        buffer.append("(")
-        for (i in 0 until children.size) {
-            buffer.append(children[i].toString())
-            buffer.append(if (i != children.size - 1) ", " else ")")
-        }
-        return buffer.toString()
-    }
-
-}

core/src/main/kotlin/org/nwapw/abacus/tree/EvaluationResult.kt

@@ -1,6 +0,0 @@
-package org.nwapw.abacus.tree
-
-import org.nwapw.abacus.context.MutableEvaluationContext
-import org.nwapw.abacus.number.NumberInterface
-
-data class EvaluationResult(val value: NumberInterface, val resultingContext: MutableEvaluationContext)

core/src/main/kotlin/org/nwapw/abacus/tree/FunctionNode.kt

@@ -1,18 +0,0 @@
-package org.nwapw.abacus.tree
-
-/**
- * A tree node that holds a function call.
- *
- * The function call node can hold any number of children, and passes the to the appropriate reducer,
- * but that is its sole purpose.
- *
- * @param function the function string.
- */
-class FunctionNode(function: String, children: List<TreeNode>) : CallNode(function, children) {
-
-    override fun <T : Any> reduce(reducer: Reducer<T>): T {
-        val children = Array<Any>(children.size, { children[it].reduce(reducer) })
-        return reducer.reduceNode(this, *children)
-    }
-
-}

core/src/main/kotlin/org/nwapw/abacus/tree/NumberBinaryNode.kt

@@ -1,22 +0,0 @@
-package org.nwapw.abacus.tree
-
-/**
- * A binary operator node that reduces its children.
- *
- * NumberBinaryNode operates by simply reducing its children and
- * then using the result of that reduction to reduce itself.
- *
- * @param operation the operation this node performs.
- * @param left the left child of this node.
- * @param right the right child of this node.
- */
-class NumberBinaryNode(operation: String, left: TreeNode, right: TreeNode)
-    : BinaryNode(operation, left, right) {
-
-    override fun <T : Any> reduce(reducer: Reducer<T>): T {
-        val left = left.reduce(reducer)
-        val right = right.reduce(reducer)
-        return reducer.reduceNode(this, left, right)
-    }
-
-}

core/src/main/kotlin/org/nwapw/abacus/tree/NumberReducer.kt

@@ -1,67 +0,0 @@
-package org.nwapw.abacus.tree
-
-import org.nwapw.abacus.Abacus
-import org.nwapw.abacus.context.EvaluationContext
-import org.nwapw.abacus.exception.EvaluationException
-import org.nwapw.abacus.number.NumberInterface
-
-class NumberReducer(val abacus: Abacus, context: EvaluationContext) : Reducer<NumberInterface> {
-
-    val context = context.mutableSubInstance()
-
-    init {
-        this.context.reducer = this
-    }
-
-    override fun reduceNode(treeNode: TreeNode, vararg children: Any): NumberInterface {
-        val promotionManager = abacus.promotionManager
-        return when(treeNode){
-            is NumberNode -> {
-                context.inheritedNumberImplementation?.instanceForString(treeNode.number)
-                        ?: throw EvaluationException("no number implementation selected.")
-            }
-            is VariableNode -> {
-                val variable = context.getVariable(treeNode.variable)
-                if(variable != null) return variable
-                val definition = context.getDefinition(treeNode.variable)
-                if(definition != null) return definition.reduce(this)
-                throw EvaluationException("variable is not defined.")
-            }
-            is NumberUnaryNode -> {
-                val child = children[0] as NumberInterface
-                context.numberImplementation = abacus.pluginManager.interfaceImplementationFor(child.javaClass)
-                abacus.pluginManager.operatorFor(treeNode.operation)
-                        .apply(context, child)
-            }
-            is NumberBinaryNode -> {
-                val left = children[0] as NumberInterface
-                val right = children[1] as NumberInterface
-                val promotionResult = promotionManager.promote(left, right) ?:
-                        throw EvaluationException("promotion failed.")
-                context.numberImplementation = promotionResult.promotedTo
-                abacus.pluginManager.operatorFor(treeNode.operation).apply(context, *promotionResult.items)
-            }
-            is FunctionNode -> {
-                val promotionResult = promotionManager
-                        .promote(*children.map { it as NumberInterface }.toTypedArray()) ?:
-                        throw EvaluationException("promotion failed.")
-                context.numberImplementation = promotionResult.promotedTo
-                abacus.pluginManager.functionFor(treeNode.callTo).apply(context, *promotionResult.items)
-            }
-            is TreeValueUnaryNode -> {
-                abacus.pluginManager.treeValueOperatorFor(treeNode.operation)
-                        .apply(context, treeNode.applyTo)
-            }
-            is TreeValueBinaryNode -> {
-                abacus.pluginManager.treeValueOperatorFor(treeNode.operation)
-                        .apply(context, treeNode.left, treeNode.right)
-            }
-            is TreeValueFunctionNode -> {
-                abacus.pluginManager.treeValueFunctionFor(treeNode.callTo)
-                        .apply(context, *treeNode.children.toTypedArray())
-            }
-            else -> throw EvaluationException("unrecognized tree node.")
-        }
-    }
-
-}

core/src/main/kotlin/org/nwapw/abacus/tree/NumberUnaryNode.kt

@@ -1,19 +0,0 @@
-package org.nwapw.abacus.tree
-
-/**
- * A unary operator node that reduces its children.
- *
- * NumberUnaryNode operates by simply reducing its child,
- * and using the result of that reduction to reduce itself.
- * @param operation the operation this node performs.
- * @param child the child this node should be applied to.
- */
-class NumberUnaryNode(operation: String, child: TreeNode)
-    : UnaryNode(operation, child) {
-
-    override fun <T : Any> reduce(reducer: Reducer<T>): T {
-        val child = applyTo.reduce(reducer)
-        return reducer.reduceNode(this, child)
-    }
-
-}

core/src/main/kotlin/org/nwapw/abacus/tree/Reducer.kt

@@ -1,19 +0,0 @@
-package org.nwapw.abacus.tree
-
-/**
- * Reducer interface that takes a tree and returns a single value.
- *
- * The reducer walks the tree, visiting the children first, converting them into
- * a value, and then attempts to reduce the parent. Eventually, the single final value is returned.
- */
-interface Reducer<out T> {
-
-    /**
-     * Reduces the given tree node, given its already reduced children.
-     *
-     * @param treeNode the tree node to reduce.
-     * @param children the list of children, of type T.
-     */
-    fun reduceNode(treeNode: TreeNode, vararg children: Any): T
-
-}

core/src/main/kotlin/org/nwapw/abacus/tree/TreeValueBinaryNode.kt

@@ -1,21 +0,0 @@
-package org.nwapw.abacus.tree
-
-/**
- * A tree node that represents a binary tree value operator.
- *
- *
- * The tree value operators operate on trees, and so this
- * node does not reduce its children. It is up to the implementation to handle
- * reduction.
- * @param operation the operation this node performs.
- * @param left the left child of this node.
- * @param right the right child of this node.
- */
-class TreeValueBinaryNode(operation: String, left: TreeNode, right: TreeNode)
-    : BinaryNode(operation, left, right) {
-
-    override fun <T : Any> reduce(reducer: Reducer<T>): T {
-        return reducer.reduceNode(this)
-    }
-
-}

core/src/main/kotlin/org/nwapw/abacus/tree/TreeValueFunctionNode.kt

@@ -1,16 +0,0 @@
-package org.nwapw.abacus.tree
-
-/**
- * A tree node that represents a tree value function call.
- *
- * This is in many ways similar to a simple FunctionNode, and the distinction
- * is mostly to help the reducer. Besides that, this class also does not
- * even attempt to reduce its children.
- */
-class TreeValueFunctionNode(name: String, children: List<TreeNode>) : CallNode(name, children) {
-
-    override fun <T : Any> reduce(reducer: Reducer<T>): T {
-        return reducer.reduceNode(this)
-    }
-
-}

core/src/main/kotlin/org/nwapw/abacus/tree/TreeValueUnaryNode.kt

@@ -1,19 +0,0 @@
-package org.nwapw.abacus.tree
-
-/**
- * A tree node that represents a unary tree value operator.
- *
- * The tree value operators operate on trees, and so this
- * node does not reduce its children. It is up to the implementation to handle
- * reduction.
- * @param operation the operation this node performs.
- * @param child the node the operation should be applied to.
- */
-class TreeValueUnaryNode(operation: String, child: TreeNode)
-    : UnaryNode(operation, child) {
-
-    override fun <T : Any> reduce(reducer: Reducer<T>): T {
-        return reducer.reduceNode(this)
-    }
-
-}

core/src/main/kotlin/org/nwapw/abacus/tree/VariableNode.kt

@@ -1,21 +0,0 @@
-package org.nwapw.abacus.tree
-
-/**
- * A tree node that holds a placeholder variable.
- *
- * This node holds a variable string, and acts similarly to a number,
- * with the key difference of not actually holding a value at runtime.
- *
- * @param variable the actual variable name that this node represents.
- */
-class VariableNode(val variable: String) : TreeNode() {
-
-    override fun <T : Any> reduce(reducer: Reducer<T>): T {
-        return reducer.reduceNode(this)
-    }
-
-    override fun toString(): String {
-        return variable
-    }
-
-}

docs/404.html

@@ -1,7 +0,0 @@
----
-layout: base 
----
-<h1>404</h1>
-
-<p><strong>Page not found :(</strong></p>
-<p>The requested page could not be found.</p>

docs/Gemfile

@@ -1,27 +0,0 @@
-source "https://rubygems.org"
-
-# Hello! This is where you manage which Jekyll version is used to run.
-# When you want to use a different version, change it below, save the
-# file and run `bundle install`. Run Jekyll with `bundle exec`, like so:
-#
-#     bundle exec jekyll serve
-#
-# This will help ensure the proper Jekyll version is running.
-# Happy Jekylling!
-gem "jekyll", "3.5.2"
-
-# This is the default theme for new Jekyll sites. You may change this to anything you like.
-gem "minima", "~> 2.0"
-
-# If you want to use GitHub Pages, remove the "gem "jekyll"" above and
-# uncomment the line below. To upgrade, run `bundle update github-pages`.
-# gem "github-pages", group: :jekyll_plugins
-
-# If you have any plugins, put them here!
-group :jekyll_plugins do
-   gem "jekyll-feed", "~> 0.6"
-end
-
-# Windows does not include zoneinfo files, so bundle the tzinfo-data gem
-gem 'tzinfo-data', platforms: [:mingw, :mswin, :x64_mingw, :jruby]
-

docs/Gemfile.lock

@@ -1,58 +0,0 @@
-GEM
-  remote: https://rubygems.org/
-  specs:
-    addressable (2.5.1)
-      public_suffix (~> 2.0, >= 2.0.2)
-    colorator (1.1.0)
-    ffi (1.9.18)
-    forwardable-extended (2.6.0)
-    jekyll (3.5.2)
-      addressable (~> 2.4)
-      colorator (~> 1.0)
-      jekyll-sass-converter (~> 1.0)
-      jekyll-watch (~> 1.1)
-      kramdown (~> 1.3)
-      liquid (~> 4.0)
-      mercenary (~> 0.3.3)
-      pathutil (~> 0.9)
-      rouge (~> 1.7)
-      safe_yaml (~> 1.0)
-    jekyll-feed (0.9.2)
-      jekyll (~> 3.3)
-    jekyll-sass-converter (1.5.0)
-      sass (~> 3.4)
-    jekyll-watch (1.5.0)
-      listen (~> 3.0, < 3.1)
-    kramdown (1.14.0)
-    liquid (4.0.0)
-    listen (3.0.8)
-      rb-fsevent (~> 0.9, >= 0.9.4)
-      rb-inotify (~> 0.9, >= 0.9.7)
-    mercenary (0.3.6)
-    minima (2.1.1)
-      jekyll (~> 3.3)
-    pathutil (0.14.0)
-      forwardable-extended (~> 2.6)
-    public_suffix (2.0.5)
-    rb-fsevent (0.10.2)
-    rb-inotify (0.9.10)
-      ffi (>= 0.5.0, < 2)
-    rouge (1.11.1)
-    safe_yaml (1.0.4)
-    sass (3.5.1)
-      sass-listen (~> 4.0.0)
-    sass-listen (4.0.0)
-      rb-fsevent (~> 0.9, >= 0.9.4)
-      rb-inotify (~> 0.9, >= 0.9.7)
-
-PLATFORMS
-  ruby
-
-DEPENDENCIES
-  jekyll (= 3.5.2)
-  jekyll-feed (~> 0.6)
-  minima (~> 2.0)
-  tzinfo-data
-
-BUNDLED WITH
-   1.15.3

docs/_config.yml

@@ -1,43 +0,0 @@
-# Welcome to Jekyll!
-#
-# This config file is meant for settings that affect your whole blog, values
-# which you are expected to set up once and rarely edit after that. If you find
-# yourself editing this file very often, consider using Jekyll's data files
-# feature for the data you need to update frequently.
-#
-# For technical reasons, this file is *NOT* reloaded automatically when you use
-# 'bundle exec jekyll serve'. If you change this file, please restart the server process.
-
-# Site settings
-# These are used to personalize your new site. If you look in the HTML files,
-# you will see them accessed via {{ site.title }}, {{ site.email }}, and so on.
-# You can create any custom variable you would like, and they will be accessible
-# in the templates via {{ site.myvariable }}.
-title: Abacus
-email: danila.fedorin@gmail.com
-description: > # this means to ignore newlines until "baseurl:"
-  This is the home page of Abacus,
-  a calculator developed during
-  the summer of 2017 as a tool
-  for the more tech-savvy users.
-baseurl: "/abacus" # the subpath of your site, e.g. /blog
-url: "htts://danilafe.github.io" # the base hostname & protocol for your site, e.g. http://example.com
-github_username: DanilaFe 
-include: ['_pages']
-
-# Build settings
-markdown: kramdown
-plugins:
-  - jekyll-feed
-
-# Exclude from processing.
-# The following items will not be processed, by default. Create a custom list
-# to override the default setting.
-# exclude:
-#   - Gemfile
-#   - Gemfile.lock
-#   - node_modules
-#   - vendor/bundle/
-#   - vendor/cache/
-#   - vendor/gems/
-#   - vendor/ruby/

docs/_includes/head.html

@@ -1,17 +0,0 @@
-<head>
-  <meta charset="utf-8">
-  <meta http-equiv="X-UA-Compatible" content="IE=edge">
-  <meta name="viewport" content="width=device-width, initial-scale=1">
-
-  <title>{% if page.title %}{{ page.title | escape }}{% else %}{{ site.title | escape }}{% endif %}</title>
-  <meta name="description" content="{{ page.excerpt | default: site.description | strip_html | normalize_whitespace | truncate: 160 | escape }}">
-
-  <link rel="stylesheet" href="{{ "assets/css/main.css" | relative_url }}">
-  <link rel="canonical" href="{{ page.url | replace:'index.html','' | absolute_url }}">
-  <link rel="alternate" type="application/rss+xml" title="{{ site.title | escape }}" href="{{ "/feed.xml" | relative_url }}">
-  
-  {% if jekyll.environment == 'production' and site.google_analytics %}
-  {% include google-analytics.html %}
-  {% endif %}
-</head>
-

docs/_includes/header.html

@@ -1,10 +0,0 @@
-<nav>
-  <div class="center">
-    <a href="{{ "/" | relative_url }}" class="primary-link">{{ site.title }}</a>
-    {% for page in site.pages %}
-    {% if page.in_header %}
-    <a href="{{ page.url | relative_url }}">{{ page.title }}</a>
-    {% endif %}
-    {% endfor %}
-  </div>
-</nav>

docs/_layouts/base.html

@@ -1,17 +0,0 @@
-<!DOCTYPE html>
-<html>
-
-  {% include head.html %}
-
-  <body>
-    {% include header.html %}
-
-    <div class="content center">
-      {{ content }}
-    </div>
-
-    {% include footer.html %}
-  </body>
-
-
-</html>

docs/_layouts/home.html

@@ -1,159 +0,0 @@
-<!DOCTYPE html>
-<html>
-  {% include head.html %}
-  <style>
-  body {
-    margin: 0px;
-    margin-top: 50px;
-    color: white;
-    text-align: center;
-  }
-  h1, h2, h3, h4, h5, h6 {
-    font-family: "Source Code Pro"
-  }
-
-  img#logo {
-    margin: auto;
-    width: 100%;
-    max-width: 100px;
-  }
-
-  img#image_preview {
-    margin: auto;
-    width: 100%;
-    max-width: 432px;
-  }
-
-  div#buttons {
-    margin-top: 40px;
-    margin-bottom: 40px;
-  }
-
-  a {
-    background-color: white;
-    color: #06e8a4;
-  }
-
-  a:hover {
-    background-color: #06e8a4;
-    color: white;
-  }
-
-  div.fullwidth {
-    width: 100%;
-    height: auto;
-    overflow: hidden;
-  }
-
-  div.fullwidth img {
-    max-width: 100%;
-    max-height: 450px;
-    margin: auto;
-    margin-top: 20px;
-    margin-bottom: 20px;
-    display: block;
-    border-radius: 5px;
-  }
-
-  div.white {
-    background-color: white;
-    color: black;
-  }
-
-  div.green {
-    background-color: #06e8a4;
-    color: white;
-  }
-
-  div.fullwidth div.double {
-    height: 100%;
-    text-align: left;
-    width: 50%;
-    box-sizing: border-box;
-    padding: 40px;
-    float: left;
-    background-color: inherit;
-  }
-
-  @media (max-width: 750px) {
-    div.fullwidth div.double {
-      width: 100%;
-      padding: 15px;
-    }
-    div.fullwidth img {
-      margin-top: 0px;
-      margin-bottom: 0px;
-    }
-  }
-
-  div.fullwidth div.double h1, h2, h3, h4, h5, h6 {
-    text-align: center;
-  }
-
-  </style>
-  <body>
-  <img src="https://raw.githubusercontent.com/DanilaFe/abacus/master/image/logo.png" id="logo">
-  <h1>Abacus</h1>
-  <h2>The programmer's calculator</h2>
-  <div id="buttons">
-    <a class="button inverted" href="{{ "/download" | relative_url }}">Download</a>
-    <a class="button inverted" href="{{ "/about" | relative_url }}">About</a>
-    <a class="button inverted" href="https://github.com/DanilaFe/abacus">Contribute</a>
-    <a class="button inverted" href="https://github.com/DanilaFe/abacus/wiki">Wiki</a>
-  </div>
-  <img src="http://i.imgur.com/Min70QY.png" title="source: imgur.com" id="image_preview"/>
-  <h2>Features</h2>
-  <div class="fullwidth white">
-    <div class="double">
-      <img src="https://i.imgur.com/gmGJBBK.png">
-    </div>
-    <div class="double">
-      <h2>Precision</h2>
-      Abacus uses a mathematical tool called Taylor Series to determine values
-      as accurate as the user desires. Of course, this comes with some
-      performance issues with larger numbers. However, Abacus has been
-      tested to generate the value of e correctly to a thousand digits.
-    </div>
-  </div>
-  <div class="fullwidth green">
-    <div class="double">
-      <h2>Configurable and Customizable</h2>
-      The very first idea for Abacus was inspired by how difficult it was
-      to program a TI-84 calculator. Only two languages were available, TI-BASIC
-      and Assembly, the latter having virtually no documentation. Determined
-      to be better than a TI-84, Abacus implemented a plugin system that allows
-      users to easily create and add plugins written in the same programming
-      language as Abacus itself - Java. These plugins can access the full
-      power of the language, and implement their own ways of handling numbers,
-      as well as their own functions and even operators.<br><br>
-      Besides the ability to add plugins, Abacus also adds some general
-      options that can be used to make the user's experience more pleasant.
-      For instance, it allows for a computation limit to be set in order
-      to prevent excessively long evaluation: 8!!! is, for example, an expression
-      that even Wolfram Alpha doesn't compute accurately, and will never finish
-      on Abacus (it's simply too large). The computation limit will allow Abacus
-      to kill a computation if it takes too long. Support for user-definable
-      precision is also planned.
-    </div>
-    <div class="double">
-      <img src="https://i.imgur.com/JzenWPV.png">
-    </div>
-  </div>
-  <div class="fullwidth white">
-    <div class="double">
-      <img src="https://i.imgur.com/jY17I3A.png">
-    </div>
-    <div class="double">
-      <h2>Built-in Documentation</h2>
-      Abacus plugins are given a mechanism to register documentation for
-      the functions that they provide. The Abacus GUI displays these
-      functions in a searchable list, allowing the user to read the parameters
-      that have to be supplied to each function, as well as learn about
-      its return value.<br><br>
-      The search finds functions not only by their names, but also by relevant
-      terms mentioned in the function's description, thus allowing related
-      functions to be displayed together.
-    </div>
-  </div>
-  </body>
-</html>

docs/_layouts/page.html

@@ -1,5 +0,0 @@
----
-layout: base
----
-<h1>{{ page.title }}</h1>
-{{ content }}

docs/_pages/about.md

@@ -1,27 +0,0 @@
----
-in_header: true
-layout: page
-title: About
-permalink: /about/
----
-
-## So... what IS Abacus?
-It's a calculator. Obviously. But what makes it better than
-what already exists? There's a few things. Abacus is:
-* Programmable, and not in TI Basic.
-* Precise. With the "precise" option, Abacus can keep up to 50 significant figures.
-* Capable. Ever wonder what 2<sup>700</sup> is? How about 8!!? Abacus can tell you!
-* Offline. While Wolfram Alpha can do powerful math, it needs internet connection!
-* Built for the desktop. Why use buttons on the screen when there's buttons on the keyboard?
-* Open source. Don't like something? Help is always welcome!
-
-## Why was Abacus made?
-The initial project was proposed for the [Northwest Advanced Programming Workshop](http://nwapw.org/about/).
-You can read the project proposal on the main GitHub page, although the idea has
-changed quite a bit, mostly in shifting from "fast" to "precise".
-
-## What is Abacus made with?
-Java and Kotlin. Java provides a good layer of abstraction and a great standard
-library, while Kotlin allows for the reduction of boilerplate code and null
-safety. Using JVM-based languages also allows Abacus to expose its entire
-API to plugins, and load them at runtime.

docs/_pages/download.md

@@ -1,34 +0,0 @@
----
-in_header: true
-layout: page
-title: Download
-permalink: /download/
----
-
-Currently, we do not provide standalone executables due to our unfamiliarity with
-including 3rd-party software. Abacus uses a number of open source libraries,
-and we do not want to breach the license terms for any of them. As soon as
-as we figure out the correct way to distribute Abacus, we will make a
-standalone distribution available. In the meantime, please use the below
-steps to run Abacus from source.
-
-## Getting the Code
-Abacus is an open source project, and is distributed under the MIT license.
-If you would like to download the source code, simply clone it from
-[GitHub](https://github.com/DanilaFe/abacus).
-Alternatively, if you don't want the bleeding edge version, check out the
-[releases](https://github.com/DanilaFe/abacus/releases).
-
-## Running from Source
-Once you have unpacked the source code, you can simply run it from
-the command line via the shell command:
-```
-./gradlew run
-```
-If you're on Windows, the command is similar:
-```
-gradlew run
-```
-This should download a distribution of Gradle, a build system that is
-used to compile Abacus. After some time, the Abacus window should appear.
-From there, you can use it normally.

docs/assets/css/main.scss

@@ -1,119 +0,0 @@
----
----
-@import url('https://fonts.googleapis.com/css?family=Source+Code+Pro|Open+Sans|Raleway');
-
-$background-color: #19d69e;
-$code-color: #efefef;
-$accent-color: #00AFE8;
-$clear-color: white;
-$title-font: "Open Sans";
-$text-font: "Raleway";
-$code-font: "Source Code Pro";
-$max-width: 850px;
-
-a {
-  text-decoration: none;
-  color: $background-color;
-
-  &.button {
-    display: inline-block;
-    background-color: $background-color;
-    color: $clear-color;
-    padding: 10px;
-    text-decoration: none;
-    border-radius: 2px;
-
-    margin: 10px;
-    transition: background-color .25s;
-
-    &:hover {
-      background-color: $clear-color;
-      color: $background-color;
-    }
-
-    &.inverted {
-      background-color: $clear-color;
-      color: $background-color;
-
-      &:hover {
-        background-color: $background-color;
-        color: $clear-color;
-      }
-    }
-  }
-}
-
-h1, h2, h3, h4, h5, h6 {
-  font: {
-    family: $title-font;
-  }
-}
-
-h1 {
-  font-size: 50px;
-}
-
-nav {
-  box-sizing: border-box;
-  background-color: $clear-color;
-  width: 100%;
-  padding: 20px;
-
-  a {
-    text-decoration: none;
-    color: $background-color;
-    font-size: 20px;
-    margin-right: 10px;
-
-    &.primary-link {
-      font-size: 30px;
-      margin-right: 20px;
-    }
-
-    &:hover {
-      color: $accent-color;
-    }
-
-    transition: color .25s;
-  }
-}
-
-body {
-  background-color: $background-color;
-  font: {
-    family: $text-font;
-  }
-  margin: 0px;
-}
-
-.center {
-  box-sizing: border-box;
-  width: 100%;
-  max-width: $max-width;
-
-  @media (min-width: $max-width) {
-    margin: {
-      left: auto;
-      right: auto;
-    }
-  }
-}
-
-.content {
-  margin-top: 20px;
-  padding: 30px;
-  background-color: $clear-color;
-}
-
-code {
-  background-color: $code-color;
-  display: inline-block;
-  padding: 5px;
-  font-family: $code-font;
-
-  pre & {
-    padding: 10px;
-    display: block;
-    width: 100%;
-  }
-}

docs/index.md

@@ -1,6 +0,0 @@
----
-# You don't need to edit this file, it's empty on purpose.
-# Edit theme's home layout instead if you wanna make some changes
-# See: https://jekyllrb.com/docs/themes/#overriding-theme-defaults
-layout: home
----

fx/build.gradle

@@ -1,8 +0,0 @@
-apply plugin: 'application'
-
-dependencies {
-    compile 'com.moandjiezana.toml:toml4j:0.7.1'
-    compile project(':core')
-}
-
-mainClassName = 'org.nwapw.abacus.fx.AbacusApplication'

fx/src/main/java/org/nwapw/abacus/fx/DocumentationCell.java

@@ -1,59 +0,0 @@
-package org.nwapw.abacus.fx;
-
-import javafx.scene.control.Label;
-import javafx.scene.control.ListCell;
-import javafx.scene.control.TitledPane;
-import javafx.scene.layout.VBox;
-import org.nwapw.abacus.function.Documentation;
-
-public class DocumentationCell extends ListCell<Documentation> {
-
-    private Label codeNameLabel;
-    private Label nameLabel;
-    private Label description;
-    private Label longDescription;
-    private TitledPane titledPane;
-
-    public DocumentationCell() {
-        VBox vbox = new VBox();
-        vbox.setSpacing(10);
-        titledPane = new TitledPane();
-        codeNameLabel = new Label();
-        nameLabel = new Label();
-        description = new Label();
-        longDescription = new Label();
-        codeNameLabel.setWrapText(true);
-        nameLabel.setWrapText(true);
-        description.setWrapText(true);
-        longDescription.setWrapText(true);
-        vbox.getChildren().add(codeNameLabel);
-        vbox.getChildren().add(nameLabel);
-        vbox.getChildren().add(description);
-        vbox.getChildren().add(longDescription);
-        titledPane.textProperty().bindBidirectional(codeNameLabel.textProperty());
-        titledPane.setContent(vbox);
-        titledPane.setExpanded(false);
-        titledPane.prefWidthProperty().bind(widthProperty().subtract(32));
-
-        visibleProperty().addListener((a, b, c) -> titledPane.setExpanded(false));
-    }
-
-    @Override
-    protected void updateItem(Documentation item, boolean empty) {
-        super.updateItem(item, empty);
-        if (empty) {
-            codeNameLabel.setText("");
-            nameLabel.setText("");
-            description.setText("");
-            longDescription.setText("");
-            setGraphic(null);
-        } else {
-            codeNameLabel.setText(item.getCodeName());
-            nameLabel.setText(item.getName());
-            description.setText(item.getDescription());
-            longDescription.setText(item.getLongDescription());
-            setGraphic(titledPane);
-        }
-        titledPane.setExpanded(false);
-    }
-}

fx/src/main/kotlin/org/nwapw/abacus/fx/ExtendedConfiguration.kt

@@ -1,72 +0,0 @@
-package org.nwapw.abacus.fx
-
-import com.moandjiezana.toml.Toml
-import com.moandjiezana.toml.TomlWriter
-import org.nwapw.abacus.config.Configuration
-import java.io.File
-
-/**
- * Additional settings for user interface.
- *
- * ExtendedConfiguration is used to add other settings
- * that aren't built into Abacus core, but are necessary
- * for the fx module.
- *
- * @property computationDelay the delay before which the computation stops.
- * @param implementation the number implementation, same as [Configuration.numberImplementation]
- * @param disabledPlugins the list of plugins that should be disabled, same as [Configuration.disabledPlugins]
- */
-class ExtendedConfiguration(var computationDelay: Double = 0.0,
-                     implementation: String = "<default>",
-                     disabledPlugins: Array<String> = emptyArray())
-    : Configuration(implementation, disabledPlugins) {
-
-    companion object {
-        /**
-         * The default TOML.
-         */
-        val DEFAULT_TOML_STRING = """
-            computationDelay=0.0
-            implementation="naive"
-            disabledPlugins=[]
-            """
-        /**
-         * A reader with the default TOML data.
-         */
-        val DEFAULT_TOML_READER = Toml().read(DEFAULT_TOML_STRING)
-        /**
-         * A writer used to writing the configuration to disk.
-         */
-        val DEFAULT_TOML_WRITER = TomlWriter()
-    }
-
-    /**
-     * Constructs a new configuration from a file on disk.
-     * @param tomlFile the file from disk to load.
-     */
-    constructor(tomlFile: File) : this() {
-        val toml = Toml(DEFAULT_TOML_READER)
-        if(tomlFile.exists()) toml.read(tomlFile)
-        copyFrom(toml.to(ExtendedConfiguration::class.java))
-    }
-
-    /**
-     * Copies data from another configuration into this one.
-     * @param config the configuration to copy from.
-     */
-    fun copyFrom(config: ExtendedConfiguration) {
-        computationDelay = config.computationDelay
-        numberImplementation = config.numberImplementation
-        disabledPlugins.clear()
-        disabledPlugins.addAll(config.disabledPlugins)
-    }
-
-    /**
-     * Saves this configuration to a file.
-     * @param file the file to save to.
-     */
-    fun saveTo(file: File) {
-        DEFAULT_TOML_WRITER.write(this, file)
-    }
-
-}

settings.gradle

@@ -1,2 +1 @@
 rootProject.name = 'abacus'
-include 'core', 'fx'

src/main/java/org/nwapw/abacus/Abacus.java

@@ -0,0 +1,140 @@
+package org.nwapw.abacus;
+
+import org.nwapw.abacus.config.Configuration;
+import org.nwapw.abacus.fx.AbacusApplication;
+import org.nwapw.abacus.number.NumberInterface;
+import org.nwapw.abacus.parsing.LexerTokenizer;
+import org.nwapw.abacus.parsing.ShuntingYardParser;
+import org.nwapw.abacus.parsing.TreeBuilder;
+import org.nwapw.abacus.plugin.NumberImplementation;
+import org.nwapw.abacus.plugin.PluginManager;
+import org.nwapw.abacus.plugin.StandardPlugin;
+import org.nwapw.abacus.tree.NumberReducer;
+import org.nwapw.abacus.tree.TreeNode;
+
+/**
+ * The main calculator class. This is responsible
+ * for piecing together all of the components, allowing
+ * their interaction with each other.
+ */
+public class Abacus {
+
+    /**
+     * The default number implementation to be used if no other one is available / selected.
+     */
+    public static final NumberImplementation DEFAULT_IMPLEMENTATION = StandardPlugin.IMPLEMENTATION_NAIVE;
+
+    /**
+     * The plugin manager responsible for
+     * loading and unloading plugins,
+     * and getting functions from them.
+     */
+    private PluginManager pluginManager;
+    /**
+     * The reducer used to evaluate the tree.
+     */
+    private NumberReducer numberReducer;
+    /**
+     * The configuration loaded from a file.
+     */
+    private Configuration configuration;
+    /**
+     * The tree builder used to construct a tree
+     * from a string.
+     */
+    private TreeBuilder treeBuilder;
+
+    /**
+     * Creates a new instance of the Abacus calculator.
+     *
+     * @param configuration the configuration object for this Abacus instance.
+     */
+    public Abacus(Configuration configuration) {
+        pluginManager = new PluginManager(this);
+        numberReducer = new NumberReducer(this);
+        this.configuration = new Configuration(configuration);
+        LexerTokenizer lexerTokenizer = new LexerTokenizer();
+        ShuntingYardParser shuntingYardParser = new ShuntingYardParser(this);
+        treeBuilder = new TreeBuilder<>(lexerTokenizer, shuntingYardParser);
+
+        pluginManager.addListener(shuntingYardParser);
+        pluginManager.addListener(lexerTokenizer);
+    }
+
+    public static void main(String[] args) {
+        AbacusApplication.launch(AbacusApplication.class, args);
+    }
+
+    /**
+     * Gets the current tree builder.
+     *
+     * @return the main tree builder in this abacus instance.
+     */
+    public TreeBuilder getTreeBuilder() {
+        return treeBuilder;
+    }
+
+    /**
+     * Gets the current plugin manager,
+     *
+     * @return the plugin manager in this abacus instance.
+     */
+    public PluginManager getPluginManager() {
+        return pluginManager;
+    }
+
+    /**
+     * Get the reducer that is responsible for transforming
+     * an expression into a number.
+     *
+     * @return the number reducer in this abacus instance.
+     */
+    public NumberReducer getNumberReducer() {
+        return numberReducer;
+    }
+
+    /**
+     * Gets the configuration object associated with this instance.
+     *
+     * @return the configuration object.
+     */
+    public Configuration getConfiguration() {
+        return configuration;
+    }
+
+    /**
+     * Parses a string into a tree structure using the main
+     * tree builder.
+     *
+     * @param input the input string to parse
+     * @return the resulting tree, null if the tree builder or the produced tree are null.
+     */
+    public TreeNode parseString(String input) {
+        return treeBuilder.fromString(input);
+    }
+
+    /**
+     * Evaluates the given tree using the main
+     * number reducer.
+     *
+     * @param tree the tree to reduce, must not be null.
+     * @return the resulting number, or null of the reduction failed.
+     */
+    public NumberInterface evaluateTree(TreeNode tree) {
+        return tree.reduce(numberReducer);
+    }
+
+    /**
+     * Creates a number from a string.
+     *
+     * @param numberString the string to create the number from.
+     * @return the resulting number.
+     */
+    public NumberInterface numberFromString(String numberString) {
+        NumberImplementation toInstantiate =
+                pluginManager.numberImplementationFor(configuration.getNumberImplementation());
+        if (toInstantiate == null) toInstantiate = DEFAULT_IMPLEMENTATION;
+
+        return toInstantiate.instanceForString(numberString);
+    }
+}

src/main/java/org/nwapw/abacus/config/Configuration.java

@@ -0,0 +1,159 @@
+package org.nwapw.abacus.config;
+
+import com.moandjiezana.toml.Toml;
+import com.moandjiezana.toml.TomlWriter;
+
+import java.io.File;
+import java.io.IOException;
+import java.util.Arrays;
+import java.util.HashSet;
+import java.util.Set;
+
+/**
+ * The configuration object that stores
+ * options that the user can change.
+ */
+public class Configuration {
+
+    /**
+     * The defaults TOML string.
+     */
+    private static final String DEFAULT_CONFIG =
+            "numberImplementation = \"naive\"\n" +
+                    "disabledPlugins = []";
+    /**
+     * The defaults TOML object, parsed from the string.
+     */
+    private static final Toml DEFAULT_TOML = new Toml().read(DEFAULT_CONFIG);
+    /**
+     * The TOML writer used to write this configuration to a file.
+     */
+    private static final TomlWriter TOML_WRITER = new TomlWriter();
+
+    /**
+     * The computation delay for which the thread can run without interruption.
+     */
+    private double computationDelay = 0;
+    /**
+     * The implementation of the number that should be used.
+     */
+    private String numberImplementation = "<default>";
+    /**
+     * The list of disabled plugins in this Configuration.
+     */
+    private Set<String> disabledPlugins = new HashSet<>();
+
+    /**
+     * Creates a new configuration form the given configuration.
+     *
+     * @param copyFrom the configuration to copy.
+     */
+    public Configuration(Configuration copyFrom){
+        copyFrom(copyFrom);
+    }
+
+    /**
+     * Creates a new configuration with the given values.
+     *
+     * @param computationDelay     the delay before the computation gets killed.
+     * @param numberImplementation the number implementation, like "naive" or "precise"
+     * @param disabledPlugins      the list of disabled plugins.
+     */
+    public Configuration(double computationDelay, String numberImplementation, String[] disabledPlugins) {
+        this.computationDelay = computationDelay;
+        this.numberImplementation = numberImplementation;
+        this.disabledPlugins.addAll(Arrays.asList(disabledPlugins));
+    }
+
+    /**
+     * Loads a configuration from a given file, keeping non-specified fields default.
+     *
+     * @param fromFile the file to load from.
+     */
+    public Configuration(File fromFile) {
+        if (!fromFile.exists()) return;
+        copyFrom(new Toml(DEFAULT_TOML).read(fromFile).to(Configuration.class));
+    }
+
+    /**
+     * Copies the values from the given configuration into this one.
+     *
+     * @param otherConfiguration the configuration to copy from.
+     */
+    public void copyFrom(Configuration otherConfiguration) {
+        this.computationDelay = otherConfiguration.computationDelay;
+        this.numberImplementation = otherConfiguration.numberImplementation;
+        this.disabledPlugins.addAll(otherConfiguration.disabledPlugins);
+    }
+
+    /**
+     * Saves this configuration to the given file, creating
+     * any directories that do not exist.
+     *
+     * @param file the file to save to.
+     */
+    public void saveTo(File file) {
+        if (file.getParentFile() != null) file.getParentFile().mkdirs();
+        try {
+            TOML_WRITER.write(this, file);
+        } catch (IOException e) {
+            e.printStackTrace();
+        }
+    }
+
+    /**
+     * Gets the value of this configuration as a string.
+     *
+     * @return the string that represents this configuration.
+     */
+    public String asTomlString(){
+        return TOML_WRITER.write(this);
+    }
+
+    /**
+     * Gets the number implementation from this configuration.
+     *
+     * @return the number implementation.
+     */
+    public String getNumberImplementation() {
+        return numberImplementation;
+    }
+
+    /**
+     * Sets the number implementation for the configuration
+     *
+     * @param numberImplementation the number implementation.
+     */
+    public void setNumberImplementation(String numberImplementation) {
+        this.numberImplementation = numberImplementation;
+    }
+
+    /**
+     * Gets the list of disabled plugins.
+     *
+     * @return the list of disabled plugins.
+     */
+    public Set<String> getDisabledPlugins() {
+        return disabledPlugins;
+    }
+
+
+    /**
+     * Gets the computation delay specified in the configuration.
+     *
+     * @return the computaton delay.
+     */
+    public double getComputationDelay() {
+        return computationDelay;
+    }
+
+    /**
+     * Sets the computation delay.
+     *
+     * @param computationDelay the new computation delay.
+     */
+    public void setComputationDelay(double computationDelay) {
+        this.computationDelay = computationDelay;
+    }
+
+}

src/main/java/org/nwapw/abacus/function/Function.java

@@ -0,0 +1,39 @@
+package org.nwapw.abacus.function;
+
+import org.nwapw.abacus.number.NumberInterface;
+
+/**
+ * A function that operates on one or more
+ * inputs and returns a single number.
+ */
+public abstract class Function {
+
+    /**
+     * Checks whether the given params will work for the given function.
+     *
+     * @param params the given params
+     * @return true if the params can be used with this function.
+     */
+    protected abstract boolean matchesParams(NumberInterface[] params);
+
+    /**
+     * Internal apply implementation, which already receives appropriately promoted
+     * parameters that have bee run through matchesParams
+     *
+     * @param params the promoted parameters.
+     * @return the return value of the function.
+     */
+    protected abstract NumberInterface applyInternal(NumberInterface[] params);
+
+    /**
+     * Function to check, promote arguments and run the function.
+     *
+     * @param params the raw input parameters.
+     * @return the return value of the function, or null if an error occurred.
+     */
+    public NumberInterface apply(NumberInterface... params) {
+        if (!matchesParams(params)) return null;
+        return applyInternal(params);
+    }
+
+}

src/main/java/org/nwapw/abacus/fx/AbacusApplication.java

@@ -17,10 +17,6 @@ public class AbacusApplication extends Application {
      */
     private AbacusController controller;
 
-    public static void main(String[] args) {
-        launch(args);
-    }
-
     @Override
     public void start(Stage primaryStage) throws Exception {
         FXMLLoader loader = new FXMLLoader(getClass().getResource("/abacus.fxml"));
@@ -37,5 +33,4 @@ public class AbacusApplication extends Application {
         super.stop();
         controller.performStop();
     }
-
 }

src/main/java/org/nwapw/abacus/fx/AbacusController.java

@@ -1,6 +1,8 @@
 package org.nwapw.abacus.fx;
 
 import javafx.application.Platform;
+import javafx.beans.value.ChangeListener;
+import javafx.beans.value.ObservableValue;
 import javafx.collections.FXCollections;
 import javafx.collections.ObservableList;
 import javafx.collections.transformation.FilteredList;
@@ -12,26 +14,17 @@ import javafx.util.Callback;
 import javafx.util.StringConverter;
 import org.nwapw.abacus.Abacus;
 import org.nwapw.abacus.config.Configuration;
-import org.nwapw.abacus.exception.AbacusException;
+import org.nwapw.abacus.number.ComputationInterruptedException;
-import org.nwapw.abacus.exception.ComputationInterruptedException;
+import org.nwapw.abacus.number.NumberInterface;
-import org.nwapw.abacus.function.Documentation;
-import org.nwapw.abacus.function.DocumentationType;
-import org.nwapw.abacus.exception.DomainException;
-import org.nwapw.abacus.exception.EvaluationException;
-import org.nwapw.abacus.number.*;
 import org.nwapw.abacus.plugin.ClassFinder;
 import org.nwapw.abacus.plugin.PluginListener;
 import org.nwapw.abacus.plugin.PluginManager;
 import org.nwapw.abacus.plugin.StandardPlugin;
-import org.nwapw.abacus.tree.EvaluationResult;
 import org.nwapw.abacus.tree.TreeNode;
 
 import java.io.File;
 import java.io.IOException;
-import java.util.ArrayList;
-import java.util.Comparator;
 import java.util.Set;
-import java.util.stream.Collectors;
 
 
 /**
@@ -104,7 +97,7 @@ public class AbacusController implements PluginListener {
     @FXML
     private TextField computationLimitField;
     @FXML
-    private ListView<Documentation> functionListView;
+    private ListView<String> functionListView;
     @FXML
     private TextField functionListSearchField;
 
@@ -127,36 +120,61 @@ public class AbacusController implements PluginListener {
     /**
      * The list of functions that are registered in the calculator.
      */
-    private ObservableList<Documentation> functionList;
+    private ObservableList<String> functionList;
     /**
      * The filtered list displayed to the user.
      */
-    private FilteredList<Documentation> functionFilter;
+    private FilteredList<String> functionFilter;
 
     /**
      * The abacus instance used for changing the plugin configuration.
      */
     private Abacus abacus;
+
+    /**
+     * Boolean which represents whether changes were made to the configuration.
+     */
+    private boolean changesMade;
+    /**
+     * Whether an alert about changes to the configuration was already shown.
+     */
+    private boolean reloadAlertShown;
+    /**
+     * The alert shown when a press to "apply" is needed.
+     */
+    private Alert reloadAlert;
+    /**
+     * The runnable that takes care of killing computations that take too long.
+     */
+    private final Runnable TIMER_RUNNABLE = () -> {
+        try {
+            Configuration abacusConfig = abacus.getConfiguration();
+            if(abacusConfig.getComputationDelay() == 0) return;
+            Thread.sleep((long) (abacusConfig.getComputationDelay() * 1000));
+            performStop();
+        } catch (InterruptedException e) { }
+    };
     /**
      * The runnable used to perform the calculation.
      */
     private final Runnable CALCULATION_RUNNABLE = new Runnable() {
 
-        private String attemptCalculation() {
+        private String attemptCalculation(){
             try {
                 TreeNode constructedTree = abacus.parseString(inputField.getText());
                 if (constructedTree == null) {
                     return ERR_SYNTAX;
                 }
-                EvaluationResult result = abacus.evaluateTree(constructedTree);
+                NumberInterface evaluatedNumber = abacus.evaluateTree(constructedTree);
-                NumberInterface evaluatedNumber = result.getValue();
+                if (evaluatedNumber == null) {
+                    return ERR_EVAL;
+                }
                 String resultingString = evaluatedNumber.toString();
                 historyData.add(new HistoryModel(inputField.getText(), constructedTree.toString(), resultingString));
-                abacus.applyToContext(result.getResultingContext());
                 return resultingString;
-            } catch (AbacusException exception) {
+            } catch (ComputationInterruptedException exception) {
-                return exception.getMessage();
+                return ERR_STOP;
-            } catch (RuntimeException exception) {
+            } catch (RuntimeException exception){
                 exception.printStackTrace();
                 return ERR_EXCEPTION;
             }
@@ -173,18 +191,6 @@ public class AbacusController implements PluginListener {
             });
         }
     };
-    /**
-     * Boolean which represents whether changes were made to the configuration.
-     */
-    private boolean changesMade;
-    /**
-     * Whether an alert about changes to the configuration was already shown.
-     */
-    private boolean reloadAlertShown;
-    /**
-     * The alert shown when a press to "apply" is needed.
-     */
-    private Alert reloadAlert;
     /**
      * The thread that is waiting to pause the calculation.
      */
@@ -193,18 +199,6 @@ public class AbacusController implements PluginListener {
      * The thread in which the computation runs.
      */
     private Thread calculationThread;
-    /**
-     * The runnable that takes care of killing computations that take too long.
-     */
-    private final Runnable TIMER_RUNNABLE = () -> {
-        try {
-            ExtendedConfiguration abacusConfig = (ExtendedConfiguration) abacus.getConfiguration();
-            if (abacusConfig.getComputationDelay() == 0) return;
-            Thread.sleep((long) (abacusConfig.getComputationDelay() * 1000));
-            performStop();
-        } catch (InterruptedException e) {
-        }
-    };
 
     /**
      * Alerts the user if the changes they made
@@ -233,12 +227,12 @@ public class AbacusController implements PluginListener {
                         return new ToggleablePlugin(string, true);
                     }
                 });
+
         functionList = FXCollections.observableArrayList();
         functionFilter = new FilteredList<>(functionList, (s) -> true);
         functionListView.setItems(functionFilter);
         functionListSearchField.textProperty().addListener((observable, oldValue, newValue) ->
-                functionFilter.setPredicate((newValue.length() == 0) ? ((s) -> true) : ((s) -> s.matches(newValue))));
+                functionFilter.setPredicate((newValue.length() == 0) ? ((s) -> true) : ((s) -> s.contains(newValue))));
-        functionListView.setCellFactory(param -> new DocumentationCell());
         historyData = FXCollections.observableArrayList();
         historyTable.setItems(historyData);
         numberImplementationOptions = FXCollections.observableArrayList();
@@ -258,14 +252,20 @@ public class AbacusController implements PluginListener {
             if (oldValue.equals(settingsTab)) alertIfApplyNeeded(true);
         });
 
-        abacus = new Abacus(new ExtendedConfiguration(CONFIG_FILE));
+        abacus = new Abacus(new Configuration(CONFIG_FILE));
         PluginManager abacusPluginManager = abacus.getPluginManager();
         abacusPluginManager.addListener(this);
-        performScan();
+        abacusPluginManager.addInstantiated(new StandardPlugin(abacus.getPluginManager()));
+        try {
+            ClassFinder.loadJars("plugins").forEach(abacusPluginManager::addClass);
+        } catch (IOException | ClassNotFoundException e) {
+            e.printStackTrace();
+        }
+        abacusPluginManager.reload();
 
-        computationLimitField.setText(Double.toString(((ExtendedConfiguration) abacus.getConfiguration()).getComputationDelay()));
+        computationLimitField.setText(Double.toString(abacus.getConfiguration().getComputationDelay()));
         computationLimitField.textProperty().addListener((observable, oldValue, newValue) -> {
-            if (!newValue.matches("(\\d+(\\.\\d*)?)?")) {
+            if(!newValue.matches("(\\d+(\\.\\d*)?)?")) {
                 computationLimitField.setText(oldValue);
             } else {
                 changesMade = true;
@@ -292,12 +292,12 @@ public class AbacusController implements PluginListener {
     }
 
     @FXML
-    public void performStop() {
+    public void performStop(){
-        if (calculationThread != null) {
+        if(calculationThread != null) {
             calculationThread.interrupt();
             calculationThread = null;
         }
-        if (computationLimitThread != null) {
+        if(computationLimitThread != null){
             computationLimitThread.interrupt();
             computationLimitThread = null;
         }
@@ -311,23 +311,10 @@ public class AbacusController implements PluginListener {
         reloadAlertShown = false;
     }
 
-    @FXML
-    public void performScan() {
-        PluginManager abacusPluginManager = abacus.getPluginManager();
-        abacusPluginManager.removeAll();
-        abacusPluginManager.addInstantiated(new StandardPlugin(abacus.getPluginManager()));
-        try {
-            ClassFinder.loadJars("plugins").forEach(abacusPluginManager::addClass);
-        } catch (IOException | ClassNotFoundException e) {
-            e.printStackTrace();
-        }
-        abacus.reload();
-    }
-
     @FXML
     public void performReload() {
         alertIfApplyNeeded(true);
-        abacus.reload();
+        abacus.getPluginManager().reload();
     }
 
     @FXML
@@ -339,9 +326,9 @@ public class AbacusController implements PluginListener {
         for (ToggleablePlugin pluginEntry : enabledPlugins) {
             if (!pluginEntry.isEnabled()) disabledPlugins.add(pluginEntry.getClassName());
         }
-        if (computationLimitField.getText().matches("\\d*(\\.\\d+)?") && computationLimitField.getText().length() != 0)
+        if(computationLimitField.getText().matches("\\d*(\\.\\d+)?") && computationLimitField.getText().length() != 0)
-            ((ExtendedConfiguration) configuration).setComputationDelay(Double.parseDouble(computationLimitField.getText()));
+            configuration.setComputationDelay(Double.parseDouble(computationLimitField.getText()));
-        ((ExtendedConfiguration) configuration).saveTo(CONFIG_FILE);
+        configuration.saveTo(CONFIG_FILE);
         changesMade = false;
         reloadAlertShown = false;
     }
@@ -360,17 +347,8 @@ public class AbacusController implements PluginListener {
             plugin.getEnabledProperty().addListener(e -> changesMade = true);
             enabledPlugins.add(plugin);
         }
-        PluginManager pluginManager = abacus.getPluginManager();
+        functionList.addAll(manager.getAllFunctions());
-        functionList.addAll(manager.getAllFunctions().stream().map(name -> {
+        functionList.sort(String::compareTo);
-            Documentation documentationInstance = pluginManager.documentationFor(name, DocumentationType.FUNCTION);
-            if(documentationInstance == null)
-                documentationInstance = new Documentation(name, "", "", "", DocumentationType.FUNCTION);
-            return documentationInstance;
-        })
-                .collect(Collectors.toCollection(ArrayList::new)));
-        functionList.addAll(manager.getAllTreeValueFunctions().stream().map(name -> pluginManager.documentationFor(name, DocumentationType.TREE_VALUE_FUNCTION))
-                .collect(Collectors.toCollection(ArrayList::new)));
-        functionList.sort(Comparator.comparing(Documentation::getCodeName));
     }
 
     @Override

src/main/java/org/nwapw/abacus/number/ComputationInterruptedException.java

@@ -0,0 +1,16 @@
+package org.nwapw.abacus.number;
+
+/**
+ * Exception thrown when the computation is interrupted by
+ * the user.
+ */
+public class ComputationInterruptedException extends RuntimeException {
+
+    /**
+     * Creates a new exception of this type.
+     */
+    public ComputationInterruptedException(){
+        super("Computation interrupted by user.");
+    }
+
+}

src/main/java/org/nwapw/abacus/number/NaiveNumber.java

@@ -114,13 +114,22 @@ public class NaiveNumber extends NumberInterface {
         return (int) value;
     }
 
+    @Override
+    public NumberInterface promoteToInternal(Class<? extends NumberInterface> toClass) {
+        if (toClass == this.getClass()) return this;
+        else if (toClass == PreciseNumber.class) {
+            return new PreciseNumber(Double.toString(value));
+        }
+        return null;
+    }
+
     public String toString() {
         double shiftBy = Math.pow(10, 10);
         return Double.toString(Math.round(value * shiftBy) / shiftBy);
     }
 
     @Override
-    public NumberInterface getMaxError() {
+    public NumberInterface getMaxError(){
         return new NaiveNumber(Math.pow(10, -18));
     }
 }

src/main/java/org/nwapw/abacus/number/NumberInterface.java

@@ -1,21 +1,18 @@
 package org.nwapw.abacus.number;
 
-import org.nwapw.abacus.exception.ComputationInterruptedException;
-
 /**
  * An interface used to represent a number.
  */
-public abstract class NumberInterface implements Comparable<NumberInterface> {
+public abstract class NumberInterface {
 
     /**
      * Check if the thread was interrupted and
      * throw an exception to end the computation.
      */
-    private static void checkInterrupted() {
+    private static void checkInterrupted(){
-        if (Thread.currentThread().isInterrupted())
+        if(Thread.currentThread().isInterrupted())
             throw new ComputationInterruptedException();
     }
-
     /**
      * The maximum precision to which this number operates.
      *
@@ -41,7 +38,7 @@ public abstract class NumberInterface implements Comparable<NumberInterface> {
      * @param multiplier the multiplier
      * @return the result of the multiplication.
      */
-    public final NumberInterface multiply(NumberInterface multiplier) {
+    public final NumberInterface multiply(NumberInterface multiplier){
         checkInterrupted();
         return multiplyInternal(multiplier);
     }
@@ -64,7 +61,7 @@ public abstract class NumberInterface implements Comparable<NumberInterface> {
      * @param divisor the divisor
      * @return the result of the division.
      */
-    public final NumberInterface divide(NumberInterface divisor) {
+    public final NumberInterface divide(NumberInterface divisor){
         checkInterrupted();
         return divideInternal(divisor);
     }
@@ -87,7 +84,7 @@ public abstract class NumberInterface implements Comparable<NumberInterface> {
      * @param summand the summand
      * @return the result of the summation.
      */
-    public final NumberInterface add(NumberInterface summand) {
+    public final NumberInterface add(NumberInterface summand){
         checkInterrupted();
         return addInternal(summand);
     }
@@ -110,7 +107,7 @@ public abstract class NumberInterface implements Comparable<NumberInterface> {
      * @param subtrahend the subtrahend.
      * @return the result of the subtraction.
      */
-    public final NumberInterface subtract(NumberInterface subtrahend) {
+    public final NumberInterface subtract(NumberInterface subtrahend){
         checkInterrupted();
         return subtractInternal(subtrahend);
     }
@@ -132,7 +129,7 @@ public abstract class NumberInterface implements Comparable<NumberInterface> {
      *
      * @return the new instance.
      */
-    public final NumberInterface negate() {
+    public final NumberInterface negate(){
         checkInterrupted();
         return negateInternal();
     }
@@ -153,11 +150,19 @@ public abstract class NumberInterface implements Comparable<NumberInterface> {
      * @param exponent the exponent to which to take the number.
      * @return the resulting value.
      */
-    public final NumberInterface intPow(int exponent) {
+    public final NumberInterface intPow(int exponent){
         checkInterrupted();
         return intPowInternal(exponent);
     }
 
+    /**
+     * Compares this number to another.
+     *
+     * @param number the number to compare to.
+     * @return same as Integer.compare();
+     */
+    public abstract int compareTo(NumberInterface number);
+
     /**
      * Same as Math.signum().
      *
@@ -179,7 +184,7 @@ public abstract class NumberInterface implements Comparable<NumberInterface> {
      *
      * @return the least integer bigger or equal to the number.
      */
-    public final NumberInterface ceiling() {
+    public final NumberInterface ceiling(){
         checkInterrupted();
         return ceilingInternal();
     }
@@ -198,7 +203,7 @@ public abstract class NumberInterface implements Comparable<NumberInterface> {
      *
      * @return the greatest int smaller than or equal to the number.
      */
-    public final NumberInterface floor() {
+    public final NumberInterface floor(){
         checkInterrupted();
         return floorInternal();
     }
@@ -214,10 +219,9 @@ public abstract class NumberInterface implements Comparable<NumberInterface> {
      * Returns the fractional part of the number, specifically x - floor(x).
      * Also, checks if the thread has been interrupted,
      * and if so, throws an exception.
-     *
      * @return the fractional part of the number.
      */
-    public final NumberInterface fractionalPart() {
+    public final NumberInterface fractionalPart(){
         checkInterrupted();
         return fractionalPartInternal();
     }
@@ -230,10 +234,30 @@ public abstract class NumberInterface implements Comparable<NumberInterface> {
      */
     public abstract int intValue();
 
+    /**
+     * Promotes this class to another number class.
+     *
+     * @param toClass the class to promote to.
+     * @return the resulting new instance.
+     */
+    protected abstract NumberInterface promoteToInternal(Class<? extends NumberInterface> toClass);
+
+    /**
+     * Promotes this class to another number class. Also, checks if the
+     * thread has been interrupted, and if so, throws
+     * an exception.
+     *
+     * @param toClass the class to promote to.
+     * @return the resulting new instance.
+     */
+    public final NumberInterface promoteTo(Class<? extends NumberInterface> toClass) {
+        checkInterrupted();
+        return promoteToInternal(toClass);
+    }
+
     /**
      * Returns the smallest error this instance can tolerate depending
      * on its precision and value.
-     *
      * @return the smallest error that should be permitted in calculations.
      */
     public abstract NumberInterface getMaxError();

src/main/java/org/nwapw/abacus/number/PreciseNumber.java

@@ -1,6 +1,7 @@
 package org.nwapw.abacus.number;
 
 import java.math.BigDecimal;
+import java.math.BigInteger;
 import java.math.MathContext;
 
 /**
@@ -35,7 +36,7 @@ public class PreciseNumber extends NumberInterface {
     /**
      * MathContext that is actually used in calculations.
      */
-    private static MathContext internalContext = new MathContext(outputContext.getPrecision() + numExtraInternalSigFigs);
+    private static MathContext internalContext = new MathContext(outputContext.getPrecision()+numExtraInternalSigFigs);
 
     /**
      * The value of the PreciseNumber.
@@ -61,6 +62,15 @@ public class PreciseNumber extends NumberInterface {
         this.value = value;
     }
 
+    /**
+     * Constructs a precise number from the given BigInteger.
+     *
+     * @param value a BigInteger object representing the value of the number.
+     */
+    public PreciseNumber(BigInteger value) {
+        this.value = new BigDecimal(value);
+    }
+
     @Override
     public int getMaxPrecision() {
         return internalContext.getPrecision();
@@ -129,7 +139,7 @@ public class PreciseNumber extends NumberInterface {
         int decimalIndex = str.indexOf('.');
         if (decimalIndex != -1) {
             NumberInterface floor = new PreciseNumber(str.substring(0, decimalIndex));
-            if (signum() == -1) {
+            if(signum() == -1){
                 floor = floor.subtract(ONE);
             }
             return floor;
@@ -152,13 +162,21 @@ public class PreciseNumber extends NumberInterface {
         return new PreciseNumber(value.negate());
     }
 
+    @Override
+    public NumberInterface promoteToInternal(Class<? extends NumberInterface> toClass) {
+        if (toClass == this.getClass()) {
+            return this;
+        }
+        return null;
+    }
+
     @Override
     public String toString() {
         return value.round(outputContext).toString();
     }
 
     @Override
-    public NumberInterface getMaxError() {
+    public NumberInterface getMaxError(){
-        return new PreciseNumber(value.ulp()).multiplyInternal(TEN.intPowInternal(value.precision() - internalContext.getPrecision()));
+        return new PreciseNumber(value.ulp()).multiplyInternal(TEN.intPowInternal(value.precision()-internalContext.getPrecision()));
     }
 }

src/main/java/org/nwapw/abacus/number/RationalNumber.java

@@ -0,0 +1,115 @@
+package org.nwapw.abacus.number;
+
+import org.apache.commons.math3.fraction.BigFraction;
+import org.apache.commons.math3.fraction.Fraction;
+
+import java.math.BigInteger;
+
+public class RationalNumber extends NumberInterface{
+
+    static final RationalNumber ONE = new RationalNumber(BigFraction.ONE);
+
+    /**
+     * The value of the number.
+     */
+    private BigFraction value;
+
+    /**
+     * Constructs a new instance with the given value.
+     * @param value
+     */
+    public RationalNumber(BigFraction value){
+        this.value = value;
+    }
+
+    @Override
+    public int getMaxPrecision() {
+        return 0;
+    }
+
+    @Override
+    protected NumberInterface multiplyInternal(NumberInterface multiplier) {
+        return new RationalNumber(value.multiply(((RationalNumber)multiplier).value));
+    }
+
+    @Override
+    protected NumberInterface divideInternal(NumberInterface divisor) {
+        return new RationalNumber(value.divide(((RationalNumber)divisor).value));
+    }
+
+    @Override
+    protected NumberInterface addInternal(NumberInterface summand) {
+        return new RationalNumber(value.add(((RationalNumber)summand).value));
+    }
+
+    @Override
+    protected NumberInterface subtractInternal(NumberInterface subtrahend) {
+        return new RationalNumber(value.subtract(((RationalNumber)subtrahend).value));
+    }
+
+    @Override
+    protected NumberInterface negateInternal() {
+        return new RationalNumber(value.negate());
+    }
+
+    @Override
+    protected NumberInterface intPowInternal(int exponent) {
+        return new RationalNumber(value.pow(exponent));
+    }
+
+    @Override
+    public int compareTo(NumberInterface number) {
+        return value.compareTo(((RationalNumber)number).value);
+    }
+
+    @Override
+    public int signum() {
+        return value.getNumerator().signum();
+    }
+
+    @Override
+    protected NumberInterface ceilingInternal() {
+        if(value.getNumeratorAsInt() != 1){
+            return floorInternal().add(ONE);
+        }
+        return this;
+    }
+
+    @Override
+    protected NumberInterface floorInternal() {
+        BigInteger floor = value.bigDecimalValue().toBigInteger();
+        if(value.compareTo(BigFraction.ZERO) < 0 && value.getDenominatorAsInt() != 1){
+            floor = floor.subtract(BigInteger.ONE);
+        }
+        return new RationalNumber(new BigFraction(floor));
+    }
+
+    @Override
+    protected NumberInterface fractionalPartInternal() {
+        return this.subtractInternal(floorInternal());
+    }
+
+    @Override
+    public int intValue() {
+        return 0;
+    }
+
+    @Override
+    protected NumberInterface promoteToInternal(Class<? extends NumberInterface> toClass) {
+        return null;
+    }
+
+    @Override
+    public NumberInterface getMaxError() {
+        return toPreciseNumber().getMaxError();
+    }
+
+    @Override
+    public String toString(){
+        return toPreciseNumber().toString();
+    }
+
+    PreciseNumber toPreciseNumber(){
+        return (PreciseNumber) new PreciseNumber(value.getNumerator()).divideInternal(new PreciseNumber(value.getDenominator()));
+    }
+}

src/main/java/org/nwapw/abacus/parsing/LexerTokenizer.java

@@ -34,7 +34,6 @@ public class LexerTokenizer implements Tokenizer<Match<TokenType>>, PluginListen
             register(" ", TokenType.WHITESPACE);
             register(",", TokenType.COMMA);
             register("[0-9]*(\\.[0-9]+)?", TokenType.NUM);
-            register("[a-zA-Z]+", TokenType.VARIABLE);
             register("\\(", TokenType.OPEN_PARENTH);
             register("\\)", TokenType.CLOSE_PARENTH);
         }};
@@ -50,15 +49,9 @@ public class LexerTokenizer implements Tokenizer<Match<TokenType>>, PluginListen
         for (String operator : manager.getAllOperators()) {
             lexer.register(Pattern.sanitize(operator), TokenType.OP);
         }
-        for (String operator : manager.getAllTreeValueOperators()) {
-            lexer.register(Pattern.sanitize(operator), TokenType.TREE_VALUE_OP);
-        }
         for (String function : manager.getAllFunctions()) {
             lexer.register(Pattern.sanitize(function), TokenType.FUNCTION);
         }
-        for (String function : manager.getAllTreeValueFunctions()) {
-            lexer.register(Pattern.sanitize(function), TokenType.TREE_VALUE_FUNCTION);
-        }
     }
 
     @Override
@@ -66,15 +59,9 @@ public class LexerTokenizer implements Tokenizer<Match<TokenType>>, PluginListen
         for (String operator : manager.getAllOperators()) {
             lexer.unregister(Pattern.sanitize(operator), TokenType.OP);
         }
-        for (String operator : manager.getAllTreeValueOperators()) {
-            lexer.unregister(Pattern.sanitize(operator), TokenType.TREE_VALUE_OP);
-        }
         for (String function : manager.getAllFunctions()) {
             lexer.unregister(Pattern.sanitize(function), TokenType.FUNCTION);
         }
-        for (String function : manager.getAllTreeValueFunctions()) {
-            lexer.unregister(Pattern.sanitize(function), TokenType.TREE_VALUE_FUNCTION);
-        }
     }
 
 }

src/main/java/org/nwapw/abacus/parsing/ShuntingYardParser.java

@@ -1,5 +1,6 @@
 package org.nwapw.abacus.parsing;
 
+import org.nwapw.abacus.Abacus;
 import org.nwapw.abacus.function.Operator;
 import org.nwapw.abacus.function.OperatorAssociativity;
 import org.nwapw.abacus.function.OperatorType;
@@ -16,6 +17,10 @@ import java.util.*;
  */
 public class ShuntingYardParser implements Parser<Match<TokenType>>, PluginListener {
 
+    /**
+     * The Abacus instance used to create number instances.
+     */
+    private Abacus abacus;
     /**
      * Map of operator precedences, loaded from the plugin operators.
      */
@@ -30,9 +35,12 @@ public class ShuntingYardParser implements Parser<Match<TokenType>>, PluginListe
     private Map<String, OperatorType> typeMap;
 
     /**
-     * Creates a new Shunting Yard parser.
+     * Creates a new Shunting Yard parser with the given Abacus instance.
+     *
+     * @param abacus the abacus instance.
      */
-    public ShuntingYardParser() {
+    public ShuntingYardParser(Abacus abacus) {
+        this.abacus = abacus;
         precedenceMap = new HashMap<>();
         associativityMap = new HashMap<>();
         typeMap = new HashMap<>();
@@ -53,12 +61,12 @@ public class ShuntingYardParser implements Parser<Match<TokenType>>, PluginListe
             Match<TokenType> match = from.remove(0);
             previousType = matchType;
             matchType = match.getType();
-            if (matchType == TokenType.NUM || matchType == TokenType.VARIABLE) {
+            if (matchType == TokenType.NUM) {
                 output.add(match);
-            } else if (matchType == TokenType.FUNCTION || matchType == TokenType.TREE_VALUE_FUNCTION) {
+            } else if (matchType == TokenType.FUNCTION) {
                 output.add(new Match<>("", TokenType.INTERNAL_FUNCTION_END));
                 tokenStack.push(match);
-            } else if (matchType == TokenType.OP || matchType == TokenType.TREE_VALUE_OP) {
+            } else if (matchType == TokenType.OP) {
                 String tokenString = match.getContent();
                 OperatorType type = typeMap.get(tokenString);
                 int precedence = precedenceMap.get(tokenString);
@@ -70,7 +78,7 @@ public class ShuntingYardParser implements Parser<Match<TokenType>>, PluginListe
                 }
 
                 if (tokenString.equals("-") && (previousType == null || previousType == TokenType.OP ||
-                        previousType == TokenType.TREE_VALUE_OP || previousType == TokenType.OPEN_PARENTH)) {
+                        previousType == TokenType.OPEN_PARENTH)) {
                     from.add(0, new Match<>("`", TokenType.OP));
                     continue;
                 }
@@ -78,12 +86,9 @@ public class ShuntingYardParser implements Parser<Match<TokenType>>, PluginListe
                 while (!tokenStack.empty() && type == OperatorType.BINARY_INFIX) {
                     Match<TokenType> otherMatch = tokenStack.peek();
                     TokenType otherMatchType = otherMatch.getType();
-                    if (!(otherMatchType == TokenType.OP ||
+                    if (!(otherMatchType == TokenType.OP || otherMatchType == TokenType.FUNCTION)) break;
-                            otherMatchType == TokenType.TREE_VALUE_OP ||
-                            otherMatchType == TokenType.FUNCTION ||
-                            otherMatchType == TokenType.TREE_VALUE_FUNCTION)) break;
 
-                    if (otherMatchType == TokenType.OP || otherMatchType == TokenType.TREE_VALUE_OP) {
+                    if (otherMatchType == TokenType.OP) {
                         int otherPrecedence = precedenceMap.get(otherMatch.getContent());
                         if (otherPrecedence < precedence ||
                                 (associativity == OperatorAssociativity.RIGHT && otherPrecedence == precedence)) {
@@ -108,10 +113,7 @@ public class ShuntingYardParser implements Parser<Match<TokenType>>, PluginListe
         while (!tokenStack.empty()) {
             Match<TokenType> match = tokenStack.peek();
             TokenType newMatchType = match.getType();
-            if (!(newMatchType == TokenType.OP ||
+            if (!(newMatchType == TokenType.OP || newMatchType == TokenType.FUNCTION)) return null;
-                    newMatchType == TokenType.TREE_VALUE_OP ||
-                    newMatchType == TokenType.FUNCTION ||
-                    newMatchType == TokenType.TREE_VALUE_FUNCTION)) return null;
             output.add(tokenStack.pop());
         }
         return output;
@@ -127,47 +129,31 @@ public class ShuntingYardParser implements Parser<Match<TokenType>>, PluginListe
         if (matches.size() == 0) return null;
         Match<TokenType> match = matches.remove(0);
         TokenType matchType = match.getType();
-        if (matchType == TokenType.OP || matchType == TokenType.TREE_VALUE_OP) {
+        if (matchType == TokenType.OP) {
             String operator = match.getContent();
             OperatorType type = typeMap.get(operator);
             if (type == OperatorType.BINARY_INFIX) {
                 TreeNode right = constructRecursive(matches);
                 TreeNode left = constructRecursive(matches);
                 if (left == null || right == null) return null;
-                if (matchType == TokenType.OP) {
+                else return new BinaryNode(operator, left, right);
-                    return new NumberBinaryNode(operator, left, right);
-                } else {
-                    return new TreeValueBinaryNode(operator, left, right);
-                }
             } else {
                 TreeNode applyTo = constructRecursive(matches);
                 if (applyTo == null) return null;
-                if (matchType == TokenType.OP) {
+                else return new UnaryNode(operator, applyTo);
-                    return new NumberUnaryNode(operator, applyTo);
-                } else {
-                    return new TreeValueUnaryNode(operator, applyTo);
-                }
             }
         } else if (matchType == TokenType.NUM) {
-            return new NumberNode(match.getContent());
+            return new NumberNode(abacus.numberFromString(match.getContent()));
-        } else if (matchType == TokenType.VARIABLE) {
+        } else if (matchType == TokenType.FUNCTION) {
-            return new VariableNode(match.getContent());
-        } else if (matchType == TokenType.FUNCTION || matchType == TokenType.TREE_VALUE_FUNCTION) {
             String functionName = match.getContent();
-            List<TreeNode> children = new ArrayList<>();
+            FunctionNode node = new FunctionNode(functionName);
             while (!matches.isEmpty() && matches.get(0).getType() != TokenType.INTERNAL_FUNCTION_END) {
                 TreeNode argument = constructRecursive(matches);
                 if (argument == null) return null;
-                children.add(0, argument);
+                node.prependChild(argument);
             }
             if (matches.isEmpty()) return null;
             matches.remove(0);
-            CallNode node;
-            if (matchType == TokenType.FUNCTION) {
-                node = new FunctionNode(functionName, children);
-            } else {
-                node = new TreeValueFunctionNode(functionName, children);
-            }
             return node;
         }
         return null;
@@ -176,7 +162,7 @@ public class ShuntingYardParser implements Parser<Match<TokenType>>, PluginListe
     @Override
     public TreeNode constructTree(List<Match<TokenType>> tokens) {
         tokens = intoPostfix(new ArrayList<>(tokens));
-        if (tokens == null) return null;
+        if(tokens == null) return null;
         Collections.reverse(tokens);
         TreeNode constructedTree = constructRecursive(tokens);
         return tokens.size() == 0 ? constructedTree : null;
@@ -190,12 +176,6 @@ public class ShuntingYardParser implements Parser<Match<TokenType>>, PluginListe
             associativityMap.put(operator, operatorInstance.getAssociativity());
             typeMap.put(operator, operatorInstance.getType());
         }
-        for (String operator : manager.getAllTreeValueOperators()) {
-            Operator operatorInstance = manager.treeValueOperatorFor(operator);
-            precedenceMap.put(operator, operatorInstance.getPrecedence());
-            associativityMap.put(operator, operatorInstance.getAssociativity());
-            typeMap.put(operator, operatorInstance.getType());
-        }
     }
 
     @Override

src/main/java/org/nwapw/abacus/plugin/NumberImplementation.java

@@ -14,7 +14,7 @@ public abstract class NumberImplementation {
     /**
      * The list of paths through which this implementation can be promoted.
      */
-    private Map<String, Function<NumberInterface, NumberInterface>> promotionPaths;
+    protected Map<Class<? extends NumberInterface>, Function<NumberInterface, NumberInterface>> promotionPaths;
     /**
      * The implementation class for this implementation.
      */
@@ -41,7 +41,7 @@ public abstract class NumberImplementation {
      *
      * @return the map of documentation paths.
      */
-    public final Map<String, Function<NumberInterface, NumberInterface>> getPromotionPaths() {
+    public final Map<Class<? extends NumberInterface>, Function<NumberInterface, NumberInterface>> getPromotionPaths() {
         return promotionPaths;
     }
 

src/main/java/org/nwapw/abacus/plugin/Plugin.java

@@ -1,8 +1,13 @@
 package org.nwapw.abacus.plugin;
 
-import org.nwapw.abacus.function.*;
+import org.nwapw.abacus.function.Function;
+import org.nwapw.abacus.function.Operator;
 import org.nwapw.abacus.number.NumberInterface;
 
+import java.util.HashMap;
+import java.util.Map;
+import java.util.Set;
+
 /**
  * A plugin class that can be externally implemented and loaded via the
  * plugin manager. Plugins provide functionality to the calculator
@@ -62,21 +67,10 @@ public abstract class Plugin {
      * @param name       the name to register by.
      * @param toRegister the function implementation.
      */
-    protected final void registerFunction(String name, NumberFunction toRegister) {
+    protected final void registerFunction(String name, Function toRegister) {
         manager.registerFunction(name, toRegister);
     }
 
-    /**
-     * To be used in load(). Registers a tree value function abstract class
-     * with the plugin internally, which makes it accessible to the plugin manager.
-     *
-     * @param name       the name to register by.
-     * @param toRegister the tree value function implementation.
-     */
-    protected final void registerTreeValueFunction(String name, TreeValueFunction toRegister) {
-        manager.registerTreeValueFunction(name, toRegister);
-    }
-
     /**
      * To be used in load(). Registers an operator abstract class
      * with the plugin internally, which makes it accessible to
@@ -85,22 +79,10 @@ public abstract class Plugin {
      * @param name     the name of the operator.
      * @param operator the operator to register.
      */
-    protected final void registerOperator(String name, NumberOperator operator) {
+    protected final void registerOperator(String name, Operator operator) {
         manager.registerOperator(name, operator);
     }
 
-    /**
-     * To be used in load(). Registers an operator
-     * with the plugin internally, which makes it accessible
-     * to the plugin manager.
-     *
-     * @param name     the name of the tree value operator.
-     * @param operator the tree value operator to register.
-     */
-    protected final void registerTreeValueOperator(String name, TreeValueOperator operator) {
-        manager.registerTreeValueOperator(name, operator);
-    }
-
     /**
      * To be used in load(). Registers a new number implementation with the plugin.
      * This makes it accessible to the plugin manager.
@@ -112,16 +94,6 @@ public abstract class Plugin {
         manager.registerNumberImplementation(name, implementation);
     }
 
-    /**
-     * To be used in load(). Registers a documentation instance
-     * used to explain some element of the plugin to the user.
-     *
-     * @param documentation the documentation instance.
-     */
-    protected final void registerDocumentation(Documentation documentation) {
-        manager.registerDocumentation(documentation);
-    }
-
     /**
      * Searches the PluginManager for the given function name.
      * This can be used by the plugins internally in order to call functions
@@ -130,22 +102,10 @@ public abstract class Plugin {
      * @param name the name for which to search
      * @return the resulting function, or null if none was found for that name.
      */
-    protected final NumberFunction functionFor(String name) {
+    protected final Function functionFor(String name) {
         return manager.functionFor(name);
     }
 
-    /**
-     * Searches the PluginManager for the given function name.
-     * This can be used by the plugins internally in order to call functions
-     * they do not provide.
-     *
-     * @param name the name for which to search.
-     * @return the resulting tree value function, or null if none was found for that name.
-     */
-    protected final TreeValueFunction treeValueFunctionFor(String name) {
-        return manager.treeValueFunctionFor(name);
-    }
-
     /**
      * Searches the PluginManager for the given operator name.
      * This can be used by the plugins internally in order to call
@@ -154,22 +114,10 @@ public abstract class Plugin {
      * @param name the name for which to search
      * @return the resulting operator, or null if none was found for that name.
      */
-    protected final NumberOperator operatorFor(String name) {
+    protected final Operator operatorFor(String name) {
         return manager.operatorFor(name);
     }
 
-    /**
-     * Searches the PluginManager for the given tree value operator name.
-     * This can be used by the plugins internally in order to call
-     * operations they do not provide.
-     *
-     * @param name the name for which to search.
-     * @return the resulting tree value operator, or null if none was found for that name.
-     */
-    protected final TreeValueOperator treeValueOperatorFor(String name) {
-        return manager.treeValueOperatorFor(name);
-    }
-
     /**
      * Searches the PluginManager for the given number implementation
      * name. This can be used by the plugins internally in order to find
@@ -182,17 +130,6 @@ public abstract class Plugin {
         return manager.numberImplementationFor(name);
     }
 
-    /**
-     * Searches the PluginManager for the given documentation name and type.
-     *
-     * @param name the name for which to search.
-     * @param type the type of documentation to search for.
-     * @return the found documentation, or null if none was found.
-     */
-    protected final Documentation documentationFor(String name, DocumentationType type) {
-        return manager.documentationFor(name, type);
-    }
-
     /**
      * Searches the plugin manager for a Pi value for the given number implementation.
      * This is done so that number implementations with various degrees of precision

src/main/java/org/nwapw/abacus/plugin/PluginManager.java

@@ -1,14 +1,12 @@
 package org.nwapw.abacus.plugin;
 
 import org.nwapw.abacus.Abacus;
-import org.nwapw.abacus.function.*;
+import org.nwapw.abacus.function.Function;
+import org.nwapw.abacus.function.Operator;
 import org.nwapw.abacus.number.NumberInterface;
 
 import java.lang.reflect.InvocationTargetException;
-import java.util.HashMap;
+import java.util.*;
-import java.util.HashSet;
-import java.util.Map;
-import java.util.Set;
 
 /**
  * A class that controls instances of plugins, allowing for them
@@ -27,35 +25,20 @@ public class PluginManager {
     /**
      * The map of functions registered by the plugins.
      */
-    private Map<String, NumberFunction> registeredFunctions;
+    private Map<String, Function> registeredFunctions;
-    /**
-     * The map of tree value functions regstered by the plugins.
-     */
-    private Map<String, TreeValueFunction> registeredTreeValueFunctions;
     /**
      * The map of operators registered by the plugins
      */
-    private Map<String, NumberOperator> registeredOperators;
+    private Map<String, Operator> registeredOperators;
-    /**
-     * The map of tree value operators registered by the plugins.
-     */
-    private Map<String, TreeValueOperator> registeredTreeValueOperators;
     /**
      * The map of number implementations registered by the plugins.
      */
     private Map<String, NumberImplementation> registeredNumberImplementations;
     /**
-     * The map of documentation for functions registered by the plugins.
+     * The list of number implementations that have been
+     * found by their implementation class.
      */
-    private Set<Documentation> registeredDocumentation;
+    private Map<Class<? extends NumberInterface>, NumberImplementation> cachedInterfaceImplementations;
-    /**
-     * The list of number implementation names.
-     */
-    private Map<Class<? extends NumberInterface>, String> interfaceImplementationNames;
-    /**
-     * The list of number implementations.
-     */
-    private Map<Class<? extends NumberInterface>, NumberImplementation> interfaceImplementations;
     /**
      * The pi values for each implementation class that have already been computer.
      */
@@ -80,148 +63,67 @@ public class PluginManager {
         loadedPluginClasses = new HashSet<>();
         plugins = new HashSet<>();
         registeredFunctions = new HashMap<>();
-        registeredTreeValueFunctions = new HashMap<>();
         registeredOperators = new HashMap<>();
-        registeredTreeValueOperators = new HashMap<>();
         registeredNumberImplementations = new HashMap<>();
-        registeredDocumentation = new HashSet<>();
+        cachedInterfaceImplementations = new HashMap<>();
-        interfaceImplementations = new HashMap<>();
-        interfaceImplementationNames = new HashMap<>();
         cachedPi = new HashMap<>();
         listeners = new HashSet<>();
     }
 
     /**
      * Registers a function under the given name.
-     *
      * @param name the name of the function.
      * @param function the function to register.
      */
-    public void registerFunction(String name, NumberFunction function) {
+    public void registerFunction(String name, Function function){
         registeredFunctions.put(name, function);
     }
 
-    /**
-     * Registers a tree value function under the given name.
-     *
-     * @param name     the name of the function.
-     * @param function the function to register.
-     */
-    public void registerTreeValueFunction(String name, TreeValueFunction function) {
-        registeredTreeValueFunctions.put(name, function);
-    }
-
     /**
      * Registers an operator under the given name.
-     *
      * @param name the name of the operator.
      * @param operator the operator to register.
      */
-    public void registerOperator(String name, NumberOperator operator) {
+    public void registerOperator(String name, Operator operator){
         registeredOperators.put(name, operator);
     }
 
-    /**
-     * Registers a tree value operator under the given name.
-     *
-     * @param name     the name of the tree value operator.
-     * @param operator the tree value operator to register.
-     */
-    public void registerTreeValueOperator(String name, TreeValueOperator operator) {
-        registeredTreeValueOperators.put(name, operator);
-    }
-
     /**
      * Registers a number implementation under the given name.
-     *
      * @param name the name of the number implementation.
      * @param implementation the number implementation to register.
      */
-    public void registerNumberImplementation(String name, NumberImplementation implementation) {
+    public void registerNumberImplementation(String name, NumberImplementation implementation){
         registeredNumberImplementations.put(name, implementation);
-        interfaceImplementationNames.put(implementation.getImplementation(), name);
-        interfaceImplementations.put(implementation.getImplementation(), implementation);
-        cachedPi.put(implementation.getImplementation(), implementation.instanceForPi());
-    }
-
-    /**
-     * Registers the given documentation with the plugin manager,
-     * making it accessible to the plugin manager etc.
-     *
-     * @param documentation the documentation to register.
-     */
-    public void registerDocumentation(Documentation documentation) {
-        registeredDocumentation.add(documentation);
     }
 
     /**
      * Gets the function registered under the given name.
-     *
      * @param name the name of the function.
      * @return the function, or null if it was not found.
      */
-    public NumberFunction functionFor(String name) {
+    public Function functionFor(String name){
         return registeredFunctions.get(name);
     }
 
-    /**
-     * Gets the tree value function registered under the given name.
-     *
-     * @param name the name of the function.
-     * @return the function, or null if it was not found.
-     */
-    public TreeValueFunction treeValueFunctionFor(String name) {
-        return registeredTreeValueFunctions.get(name);
-    }
-
     /**
      * Gets the operator registered under the given name.
-     *
      * @param name the name of the operator.
      * @return the operator, or null if it was not found.
      */
-    public NumberOperator operatorFor(String name) {
+    public Operator operatorFor(String name){
         return registeredOperators.get(name);
     }
 
-    /**
-     * Gets the tree value operator registered under the given name.
-     *
-     * @param name the name of the tree value operator.
-     * @return the operator, or null if it was not found.
-     */
-    public TreeValueOperator treeValueOperatorFor(String name) {
-        return registeredTreeValueOperators.get(name);
-    }
-
     /**
      * Gets the number implementation registered under the given name.
-     *
      * @param name the name of the number implementation.
      * @return the number implementation, or null if it was not found.
      */
-    public NumberImplementation numberImplementationFor(String name) {
+    public NumberImplementation numberImplementationFor(String name){
         return registeredNumberImplementations.get(name);
     }
 
-    /**
-     * Gets the documentation for the given entity of the given type.
-     *
-     * @param name the name of the entity to search for.
-     * @param type the type that this entity is, to filter out similarly named documentation.
-     * @return the documentation object.
-     */
-    public Documentation documentationFor(String name, DocumentationType type) {
-        Documentation toReturn = null;
-        for (Documentation entry : registeredDocumentation) {
-            if (entry.getCodeName().equals(name) && entry.getType() == type) {
-                toReturn = entry;
-                break;
-            }
-        }
-        return toReturn;
-    }
-
     /**
      * Gets the number implementation for the given implementation class.
      *
@@ -229,17 +131,17 @@ public class PluginManager {
      * @return the implementation.
      */
     public NumberImplementation interfaceImplementationFor(Class<? extends NumberInterface> name) {
-        return interfaceImplementations.get(name);
+        if (cachedInterfaceImplementations.containsKey(name)) return cachedInterfaceImplementations.get(name);
+        NumberImplementation toReturn = null;
+        for(String key : registeredNumberImplementations.keySet()){
+            NumberImplementation implementation = registeredNumberImplementations.get(key);
+            if(implementation.getImplementation() == name) {
+                toReturn = implementation;
+                break;
             }
-
+        }
-    /**
+        cachedInterfaceImplementations.put(name, toReturn);
-     * Gets the number implementation name for the given implementation class.
+        return toReturn;
-     *
-     * @param name the class for which to find the implementation name.
-     * @return the implementation name.
-     */
-    public String interfaceImplementationNameFor(Class<? extends NumberInterface> name) {
-        return interfaceImplementationNames.get(name);
     }
 
     /**
@@ -249,7 +151,14 @@ public class PluginManager {
      * @return pi
      */
     public NumberInterface piFor(Class<? extends NumberInterface> forClass) {
-        return cachedPi.get(forClass);
+        if (cachedPi.containsKey(forClass)) return cachedPi.get(forClass);
+        NumberImplementation implementation = interfaceImplementationFor(forClass);
+        NumberInterface generatedPi = null;
+        if (implementation != null) {
+            generatedPi = implementation.instanceForPi();
+        }
+        cachedPi.put(forClass, generatedPi);
+        return generatedPi;
     }
 
     /**
@@ -278,25 +187,6 @@ public class PluginManager {
         }
     }
 
-    /**
-     * Removes the plugin with the given class from the manager.
-     *
-     * @param toRemove the plugin to remove.
-     */
-    public void removeClass(Class<? extends Plugin> toRemove) {
-        if (!loadedPluginClasses.contains(toRemove)) return;
-        plugins.removeIf(plugin -> plugin.getClass() == toRemove);
-        loadedPluginClasses.remove(toRemove);
-    }
-
-    /**
-     * Removes all plugins from this plugin manager.
-     */
-    public void removeAll() {
-        loadedPluginClasses.clear();
-        plugins.clear();
-    }
-
     /**
      * Loads all the plugins in the PluginManager.
      */
@@ -320,13 +210,9 @@ public class PluginManager {
             plugin.disable();
         }
         registeredFunctions.clear();
-        registeredTreeValueFunctions.clear();
         registeredOperators.clear();
-        registeredTreeValueOperators.clear();
         registeredNumberImplementations.clear();
-        registeredDocumentation.clear();
+        cachedInterfaceImplementations.clear();
-        interfaceImplementationNames.clear();
-        interfaceImplementations.clear();
         cachedPi.clear();
         listeners.forEach(e -> e.onUnload(this));
     }
@@ -348,15 +234,6 @@ public class PluginManager {
         return registeredFunctions.keySet();
     }
 
-    /**
-     * Gets all the tree vlaue functions loaded by the PluginManager.
-     *
-     * @return the set of all the tree value functions that were loaded.
-     */
-    public Set<String> getAllTreeValueFunctions() {
-        return registeredTreeValueFunctions.keySet();
-    }
-
     /**
      * Gets all the operators loaded by the Plugin Manager.
      *
@@ -366,15 +243,6 @@ public class PluginManager {
         return registeredOperators.keySet();
     }
 
-    /**
-     * Gets all the tree value operators loaded by the PluginManager.
-     *
-     * @return the set of all tree value operators that were loaded.
-     */
-    public Set<String> getAllTreeValueOperators() {
-        return registeredTreeValueOperators.keySet();
-    }
-
     /**
      * Gets all the number implementations loaded by the Plugin Manager.
      *
@@ -411,5 +279,4 @@ public class PluginManager {
     public Set<Class<?>> getLoadedPluginClasses() {
         return loadedPluginClasses;
     }
-    
 }

src/main/java/org/nwapw/abacus/plugin/StandardPlugin.java

@@ -0,0 +1,577 @@
+package org.nwapw.abacus.plugin;
+
+import org.nwapw.abacus.function.Function;
+import org.nwapw.abacus.function.Operator;
+import org.nwapw.abacus.function.OperatorAssociativity;
+import org.nwapw.abacus.function.OperatorType;
+import org.nwapw.abacus.number.NaiveNumber;
+import org.nwapw.abacus.number.NumberInterface;
+import org.nwapw.abacus.number.PreciseNumber;
+
+import java.util.ArrayList;
+import java.util.HashMap;
+import java.util.function.BiFunction;
+
+/**
+ * The plugin providing standard functions such as addition and subtraction to
+ * the calculator.
+ */
+public class StandardPlugin extends Plugin {
+
+    /**
+     * Stores objects of NumberInterface with integer values for reuse.
+     */
+    private final static HashMap<Class<? extends NumberInterface>, HashMap<Integer, NumberInterface>> integerValues = new HashMap<>();
+
+    /**
+     * The addition operator, +
+     */
+    public static final Operator OP_ADD = new Operator(OperatorAssociativity.LEFT, OperatorType.BINARY_INFIX, 0, new Function() {
+        @Override
+        protected boolean matchesParams(NumberInterface[] params) {
+            return params.length >= 1;
+        }
+
+        @Override
+        protected NumberInterface applyInternal(NumberInterface[] params) {
+            NumberInterface sum = params[0];
+            for (int i = 1; i < params.length; i++) {
+                sum = sum.add(params[i]);
+            }
+            return sum;
+        }
+    });
+    /**
+     * The subtraction operator, -
+     */
+    public static final Operator OP_SUBTRACT = new Operator(OperatorAssociativity.LEFT, OperatorType.BINARY_INFIX, 0, new Function() {
+        @Override
+        protected boolean matchesParams(NumberInterface[] params) {
+            return params.length == 2;
+        }
+
+        @Override
+        protected NumberInterface applyInternal(NumberInterface[] params) {
+            return params[0].subtract(params[1]);
+
+        }
+    });
+    /**
+     * The negation operator, -
+     */
+    public static final Operator OP_NEGATE = new Operator(OperatorAssociativity.LEFT, OperatorType.UNARY_PREFIX, 0, new Function() {
+        @Override
+        protected boolean matchesParams(NumberInterface[] params) {
+            return params.length == 1;
+        }
+
+        @Override
+        protected NumberInterface applyInternal(NumberInterface[] params) {
+            return params[0].negate();
+        }
+    });
+    /**
+     * The multiplication operator, *
+     */
+    public static final Operator OP_MULTIPLY = new Operator(OperatorAssociativity.LEFT, OperatorType.BINARY_INFIX, 1, new Function() {
+        @Override
+        protected boolean matchesParams(NumberInterface[] params) {
+            return params.length >= 1;
+        }
+
+        @Override
+        protected NumberInterface applyInternal(NumberInterface[] params) {
+            NumberInterface product = params[0];
+            for (int i = 1; i < params.length; i++) {
+                product = product.multiply(params[i]);
+            }
+            return product;
+        }
+    });
+    /**
+     * The division operator, /
+     */
+    public static final Operator OP_DIVIDE = new Operator(OperatorAssociativity.LEFT, OperatorType.BINARY_INFIX, 1, new Function() {
+        @Override
+        protected boolean matchesParams(NumberInterface[] params) {
+            return params.length == 2 && params[1].compareTo(NaiveNumber.ZERO.promoteTo(params[1].getClass())) != 0;
+        }
+
+        @Override
+        protected NumberInterface applyInternal(NumberInterface[] params) {
+            return params[0].divide(params[1]);
+        }
+    });
+    /**
+     * The factorial operator, !
+     */
+    public static final Operator OP_FACTORIAL = new Operator(OperatorAssociativity.RIGHT, OperatorType.UNARY_POSTFIX, 0, new Function() {
+        //private HashMap<Class<? extends NumberInterface>, ArrayList<NumberInterface>> storedList = new HashMap<Class<? extends NumberInterface>, ArrayList<NumberInterface>>();
+        @Override
+        protected boolean matchesParams(NumberInterface[] params) {
+            return params.length == 1
+                    && params[0].fractionalPart().compareTo(NaiveNumber.ZERO.promoteTo(params[0].getClass())) == 0
+                    && params[0].signum() >= 0;
+        }
+
+        @Override
+        protected NumberInterface applyInternal(NumberInterface[] params) {
+            if (params[0].signum() == 0) {
+                return fromInt(params[0].getClass(), 1);
+            }
+            NumberInterface factorial = params[0];
+            NumberInterface multiplier = params[0];
+            //It is necessary to later prevent calls of factorial on anything but non-negative integers.
+            while ((multiplier = multiplier.subtract(NaiveNumber.ONE.promoteTo(multiplier.getClass()))).signum() == 1) {
+                factorial = factorial.multiply(multiplier);
+            }
+            return factorial;
+                /*if(!storedList.containsKey(params[0].getClass())){
+                    storedList.put(params[0].getClass(), new ArrayList<NumberInterface>());
+                    storedList.get(params[0].getClass()).add(NaiveNumber.ONE.promoteTo(params[0].getClass()));
+                    storedList.get(params[0].getClass()).add(NaiveNumber.ONE.promoteTo(params[0].getClass()));
+                }*/
+        }
+    });
+    /**
+     * The absolute value function, abs(-3) = 3
+     */
+    public static final Function FUNCTION_ABS = new Function() {
+        @Override
+        protected boolean matchesParams(NumberInterface[] params) {
+            return params.length == 1;
+        }
+
+        @Override
+        protected NumberInterface applyInternal(NumberInterface[] params) {
+            return params[0].multiply((new NaiveNumber(params[0].signum())).promoteTo(params[0].getClass()));
+        }
+    };
+    /**
+     * The natural log function.
+     */
+    public static final Function FUNCTION_LN = new Function() {
+        @Override
+        protected boolean matchesParams(NumberInterface[] params) {
+            return params.length == 1 && params[0].compareTo(NaiveNumber.ZERO.promoteTo(params[0].getClass())) > 0;
+        }
+
+        @Override
+        protected NumberInterface applyInternal(NumberInterface[] params) {
+            NumberInterface param = params[0];
+            int powersOf2 = 0;
+            while (FUNCTION_ABS.apply(param.subtract(NaiveNumber.ONE.promoteTo(param.getClass()))).compareTo(new NaiveNumber(0.1).promoteTo(param.getClass())) >= 0) {
+                if (param.subtract(NaiveNumber.ONE.promoteTo(param.getClass())).signum() == 1) {
+                    param = param.divide(fromInt(param.getClass(), 2));
+                    powersOf2++;
+                    if (param.subtract(NaiveNumber.ONE.promoteTo(param.getClass())).signum() != 1) {
+                        break;
+                        //No infinite loop for you.
+                    }
+                } else {
+                    param = param.multiply(fromInt(param.getClass(), 2));
+                    powersOf2--;
+                    if (param.subtract(NaiveNumber.ONE.promoteTo(param.getClass())).signum() != -1) {
+                        break;
+                        //No infinite loop for you.
+                    }
+                }
+            }
+            return getLog2(param).multiply((new NaiveNumber(powersOf2)).promoteTo(param.getClass())).add(getLogPartialSum(param));
+        }
+
+        /**
+         * Returns the partial sum of the Taylor series for logx (around x=1).
+         * Automatically determines the number of terms needed based on the precision of x.
+         * @param x value at which the series is evaluated. 0 < x < 2. (x=2 is convergent but impractical.)
+         * @return the partial sum.
+         */
+        private NumberInterface getLogPartialSum(NumberInterface x) {
+
+            NumberInterface maxError = x.getMaxError();
+            x = x.subtract(NaiveNumber.ONE.promoteTo(x.getClass())); //Terms used are for log(x+1).
+            NumberInterface currentNumerator = x, currentTerm = x, sum = x;
+            int n = 1;
+            while (FUNCTION_ABS.apply(currentTerm).compareTo(maxError) > 0) {
+                n++;
+                currentNumerator = currentNumerator.multiply(x).negate();
+                currentTerm = currentNumerator.divide(new NaiveNumber(n).promoteTo(x.getClass()));
+                sum = sum.add(currentTerm);
+            }
+            return sum;
+        }
+
+        /**
+         * Returns natural log of 2 to the required precision of the class of number.
+         * @param number a number of the same type as the return type. (Used for precision.)
+         * @return the value of log(2) with the appropriate precision.
+         */
+        private NumberInterface getLog2(NumberInterface number) {
+            NumberInterface maxError = number.getMaxError();
+            //NumberInterface errorBound = fromInt(number.getClass(), 1);
+            //We'll use the series \sigma_{n >= 1) ((1/3^n + 1/4^n) * 1/n)
+            //In the following, a=1/3^n, b=1/4^n, c = 1/n.
+            //a is also an error bound.
+            NumberInterface a = fromInt(number.getClass(), 1), b = a, c = a;
+            NumberInterface sum = NaiveNumber.ZERO.promoteTo(number.getClass());
+            int n = 0;
+            while (a.compareTo(maxError) >= 1) {
+                n++;
+                a = a.divide(fromInt(number.getClass(), 3));
+                b = b.divide(fromInt(number.getClass(), 4));
+                c = NaiveNumber.ONE.promoteTo(number.getClass()).divide((new NaiveNumber(n)).promoteTo(number.getClass()));
+                sum = sum.add(a.add(b).multiply(c));
+            }
+            return sum;
+        }
+    };
+    /**
+     * The square root function.
+     */
+    public static final Function FUNCTION_SQRT = new Function() {
+        @Override
+        protected boolean matchesParams(NumberInterface[] params) {
+            return params.length == 1;
+        }
+
+        @Override
+        protected NumberInterface applyInternal(NumberInterface[] params) {
+            return OP_CARET.getFunction().apply(params[0], ((new NaiveNumber(0.5)).promoteTo(params[0].getClass())));
+        }
+    };
+    /**
+     * The implementation for double-based naive numbers.
+     */
+    public static final NumberImplementation IMPLEMENTATION_NAIVE = new NumberImplementation(NaiveNumber.class, 0) {
+        @Override
+        public NumberInterface instanceForString(String string) {
+            return new NaiveNumber(string);
+        }
+
+        @Override
+        public NumberInterface instanceForPi() {
+            return new NaiveNumber(Math.PI);
+        }
+    };
+    /**
+     * The implementation for the infinite-precision BigDecimal.
+     */
+    public static final NumberImplementation IMPLEMENTATION_PRECISE = new NumberImplementation(PreciseNumber.class, 0) {
+        @Override
+        public NumberInterface instanceForString(String string) {
+            return new PreciseNumber(string);
+        }
+
+        @Override
+        public NumberInterface instanceForPi() {
+            NumberInterface C = FUNCTION_SQRT.apply(new PreciseNumber("10005")).multiply(new PreciseNumber("426880"));
+            NumberInterface M = PreciseNumber.ONE;
+            NumberInterface L = new PreciseNumber("13591409");
+            NumberInterface X = M;
+            NumberInterface sum = L;
+            int termsNeeded = C.getMaxPrecision() / 13 + 1;
+
+            NumberInterface lSummand = new PreciseNumber("545140134");
+            NumberInterface xMultiplier = new PreciseNumber("262537412")
+                    .multiply(new PreciseNumber("1000000000"))
+                    .add(new PreciseNumber("640768000"))
+                    .negate();
+            for (int i = 0; i < termsNeeded; i++) {
+                M = M
+                        .multiply(new NaiveNumber(12 * i + 2).promoteTo(PreciseNumber.class))
+                        .multiply(new NaiveNumber(12 * i + 6).promoteTo(PreciseNumber.class))
+                        .multiply(new NaiveNumber(12 * i + 10).promoteTo(PreciseNumber.class))
+                        .divide(new NaiveNumber(Math.pow(i + 1, 3)).promoteTo(PreciseNumber.class));
+                L = L.add(lSummand);
+                X = X.multiply(xMultiplier);
+                sum = sum.add(M.multiply(L).divide(X));
+            }
+            return C.divide(sum);
+        }
+    };
+    private static final HashMap<Class<? extends NumberInterface>, ArrayList<NumberInterface>> FACTORIAL_LISTS = new HashMap<>();
+    /**
+     * The exponential function, exp(1) = e^1 = 2.71...
+     */
+    public static final Function FUNCTION_EXP = new Function() {
+        @Override
+        protected boolean matchesParams(NumberInterface[] params) {
+            return params.length == 1;
+        }
+
+        @Override
+        protected NumberInterface applyInternal(NumberInterface[] params) {
+            NumberInterface maxError = params[0].getMaxError();
+            int n = 0;
+            if (params[0].signum() < 0) {
+                NumberInterface[] negatedParams = {params[0].negate()};
+               return fromInt(params[0].getClass(), 1).divide(applyInternal(negatedParams));
+            } else {
+                //We need n such that x^(n+1) * 3^ceil(x) <= maxError * (n+1)!.
+                //right and left refer to lhs and rhs in the above inequality.
+                NumberInterface sum = NaiveNumber.ONE.promoteTo(params[0].getClass());
+                NumberInterface nextNumerator = params[0];
+                NumberInterface left = params[0].multiply(fromInt(params[0].getClass(), 3).intPow(params[0].ceiling().intValue())), right = maxError;
+                do {
+                    sum = sum.add(nextNumerator.divide(factorial(params[0].getClass(), n + 1)));
+                    n++;
+                    nextNumerator = nextNumerator.multiply(params[0]);
+                    left = left.multiply(params[0]);
+                    NumberInterface nextN = (new NaiveNumber(n + 1)).promoteTo(params[0].getClass());
+                    right = right.multiply(nextN);
+                    //System.out.println(left + ", " + right);
+                }
+                while (left.compareTo(right) > 0);
+                //System.out.println(n+1);
+                return sum;
+            }
+        }
+    };
+    /**
+     * The caret / pow operator, ^
+     */
+    public static final Operator OP_CARET = new Operator(OperatorAssociativity.RIGHT, OperatorType.BINARY_INFIX, 2, new Function() {
+        @Override
+        protected boolean matchesParams(NumberInterface[] params) {
+            return params.length == 2
+                    && !(params[0].compareTo(NaiveNumber.ZERO.promoteTo(params[0].getClass())) == 0
+                    && params[1].compareTo(NaiveNumber.ZERO.promoteTo(params[1].getClass())) == 0)
+                    && !(params[0].signum() == -1 && params[1].fractionalPart().compareTo(NaiveNumber.ZERO.promoteTo(params[1].getClass())) != 0);
+        }
+
+        @Override
+        protected NumberInterface applyInternal(NumberInterface[] params) {
+            if (params[0].compareTo(NaiveNumber.ZERO.promoteTo(params[0].getClass())) == 0)
+                return NaiveNumber.ZERO.promoteTo(params[0].getClass());
+            else if (params[1].compareTo(NaiveNumber.ZERO.promoteTo(params[0].getClass())) == 0)
+                return NaiveNumber.ONE.promoteTo(params[1].getClass());
+            //Detect integer bases:
+            if(params[0].fractionalPart().compareTo(fromInt(params[0].getClass(), 0)) == 0
+                    && FUNCTION_ABS.apply(params[1]).compareTo(fromInt(params[0].getClass(), Integer.MAX_VALUE)) < 0
+                    && FUNCTION_ABS.apply(params[1]).compareTo(fromInt(params[1].getClass(), 1)) >= 0){
+                NumberInterface[] newParams = {params[0], params[1].fractionalPart()};
+                return params[0].intPow(params[1].floor().intValue()).multiply(applyInternal(newParams));
+            }
+            return FUNCTION_EXP.apply(FUNCTION_LN.apply(FUNCTION_ABS.apply(params[0])).multiply(params[1]));
+        }
+    });
+    /**
+     * The sine function (the argument is interpreted in radians).
+     */
+    public final Function functionSin = new Function() {
+        @Override
+        protected boolean matchesParams(NumberInterface[] params) {
+            return params.length == 1;
+        }
+
+        @Override
+        protected NumberInterface applyInternal(NumberInterface[] params) {
+            NumberInterface pi = piFor(params[0].getClass());
+            NumberInterface twoPi = pi.multiply(fromInt(pi.getClass(), 2));
+            NumberInterface theta = getSmallAngle(params[0], pi);
+            //System.out.println(theta);
+            if (theta.compareTo(pi.multiply(new NaiveNumber(1.5).promoteTo(twoPi.getClass()))) >= 0) {
+                theta = theta.subtract(twoPi);
+            } else if (theta.compareTo(pi.divide(fromInt(pi.getClass(), 2))) > 0) {
+                theta = pi.subtract(theta);
+            }
+            //System.out.println(theta);
+            return sinTaylor(theta);
+        }
+    };
+    /**
+     * The cosine function (the argument is in radians).
+     */
+    public final Function functionCos = new Function() {
+        @Override
+        protected boolean matchesParams(NumberInterface[] params) {
+            return params.length == 1;
+        }
+
+        @Override
+        protected NumberInterface applyInternal(NumberInterface[] params) {
+            return functionSin.apply(piFor(params[0].getClass()).divide(fromInt(params[0].getClass(), 2))
+                    .subtract(params[0]));
+        }
+    };
+    /**
+     * The tangent function (the argument is in radians).
+     */
+    public final Function functionTan = new Function() {
+        @Override
+        protected boolean matchesParams(NumberInterface[] params) {
+            return params.length == 1;
+        }
+
+        @Override
+        protected NumberInterface applyInternal(NumberInterface[] params) {
+            return functionSin.apply(params[0]).divide(functionCos.apply(params[0]));
+        }
+    };
+    /**
+     * The secant function (the argument is in radians).
+     */
+    public final Function functionSec = new Function() {
+        @Override
+        protected boolean matchesParams(NumberInterface[] params) {
+            return params.length == 1;
+        }
+
+        @Override
+        protected NumberInterface applyInternal(NumberInterface[] params) {
+            return NaiveNumber.ONE.promoteTo(params[0].getClass()).divide(functionCos.apply(params[0]));
+        }
+    };
+    /**
+     * The cosecant function (the argument is in radians).
+     */
+    public final Function functionCsc = new Function() {
+        @Override
+        protected boolean matchesParams(NumberInterface[] params) {
+            return params.length == 1;
+        }
+
+        @Override
+        protected NumberInterface applyInternal(NumberInterface[] params) {
+            return NaiveNumber.ONE.promoteTo(params[0].getClass()).divide(functionSin.apply(params[0]));
+        }
+    };
+    /**
+     * The cotangent function (the argument is in radians).
+     */
+    public final Function functionCot = new Function() {
+        @Override
+        protected boolean matchesParams(NumberInterface[] params) {
+            return params.length == 1;
+        }
+
+        @Override
+        protected NumberInterface applyInternal(NumberInterface[] params) {
+            return functionCos.apply(params[0]).divide(functionSin.apply(params[0]));
+        }
+    };
+
+    public StandardPlugin(PluginManager manager) {
+        super(manager);
+    }
+
+    /**
+     * Returns a partial sum of a series whose terms are given by the nthTermFunction, evaluated at x.
+     *
+     * @param x               the value at which the series is evaluated.
+     * @param nthTermFunction the function that returns the nth term of the series, in the format term(x, n).
+     * @param n               the number of terms in the partial sum.
+     * @return the value of the partial sum that has the same class as x.
+     */
+    private static NumberInterface sumSeries(NumberInterface x, BiFunction<Integer, NumberInterface, NumberInterface> nthTermFunction, int n) {
+        NumberInterface sum = NaiveNumber.ZERO.promoteTo(x.getClass());
+        for (int i = 0; i <= n; i++) {
+            sum = sum.add(nthTermFunction.apply(i, x));
+        }
+        return sum;
+    }
+
+    /**
+     * A factorial function that uses memoization for each number class; it efficiently
+     * computes factorials of non-negative integers.
+     *
+     * @param numberClass type of number to return.
+     * @param n           non-negative integer.
+     * @return a number of numClass with value n factorial.
+     */
+    public static NumberInterface factorial(Class<? extends NumberInterface> numberClass, int n) {
+        if (!FACTORIAL_LISTS.containsKey(numberClass)) {
+            FACTORIAL_LISTS.put(numberClass, new ArrayList<>());
+            FACTORIAL_LISTS.get(numberClass).add(NaiveNumber.ONE.promoteTo(numberClass));
+            FACTORIAL_LISTS.get(numberClass).add(NaiveNumber.ONE.promoteTo(numberClass));
+        }
+        ArrayList<NumberInterface> list = FACTORIAL_LISTS.get(numberClass);
+        if (n >= list.size()) {
+            while (list.size() < n + 16) {
+                list.add(list.get(list.size() - 1).multiply(new NaiveNumber(list.size()).promoteTo(numberClass)));
+            }
+        }
+        return list.get(n);
+    }
+
+    /**
+     * Returns the value of the Taylor series for sin (centered at 0) at x.
+     *
+     * @param x where the series is evaluated.
+     * @return the value of the series
+     */
+    private static NumberInterface sinTaylor(NumberInterface x) {
+        NumberInterface power = x, multiplier = x.multiply(x).negate(), currentTerm = x, sum = x;
+        NumberInterface maxError = x.getMaxError();
+        int n = 1;
+        do {
+            n += 2;
+            power = power.multiply(multiplier);
+            currentTerm = power.divide(factorial(x.getClass(), n));
+            sum = sum.add(currentTerm);
+        } while (FUNCTION_ABS.apply(currentTerm).compareTo(maxError) > 0);
+        return sum;
+    }
+
+    /**
+     * Returns an equivalent angle in the interval [0, 2pi)
+     *
+     * @param phi an angle (in radians).
+     * @return theta in [0, 2pi) that differs from phi by a multiple of 2pi.
+     */
+    private static NumberInterface getSmallAngle(NumberInterface phi, NumberInterface pi) {
+        NumberInterface twoPi = pi.multiply(new NaiveNumber("2").promoteTo(phi.getClass()));
+        NumberInterface theta = FUNCTION_ABS.apply(phi).subtract(twoPi
+                .multiply(FUNCTION_ABS.apply(phi).divide(twoPi).floor())); //Now theta is in [0, 2pi).
+        if (phi.signum() < 0) {
+            theta = twoPi.subtract(theta);
+        }
+        return theta;
+    }
+
+    /**
+     * Returns a number of class numType with value n.
+     * @param numType class of number to return.
+     * @param n value of returned number.
+     * @return numClass instance with value n.
+     */
+    private static NumberInterface fromInt(Class<? extends NumberInterface> numType, int n){
+        if(!integerValues.containsKey(numType)){
+            integerValues.put(numType, new HashMap<>());
+        }
+        if(!integerValues.get(numType).containsKey(n)){
+            integerValues.get(numType).put(n, new NaiveNumber(n).promoteTo(numType));
+        }
+        return integerValues.get(numType).get(n);
+    }
+
+    @Override
+    public void onEnable() {
+        registerNumberImplementation("naive", IMPLEMENTATION_NAIVE);
+        registerNumberImplementation("precise", IMPLEMENTATION_PRECISE);
+
+        registerOperator("+", OP_ADD);
+        registerOperator("-", OP_SUBTRACT);
+        registerOperator("`", OP_NEGATE);
+        registerOperator("*", OP_MULTIPLY);
+        registerOperator("/", OP_DIVIDE);
+        registerOperator("^", OP_CARET);
+        registerOperator("!", OP_FACTORIAL);
+
+        registerFunction("abs", FUNCTION_ABS);
+        registerFunction("exp", FUNCTION_EXP);
+        registerFunction("ln", FUNCTION_LN);
+        registerFunction("sqrt", FUNCTION_SQRT);
+        registerFunction("sin", functionSin);
+        registerFunction("cos", functionCos);
+        registerFunction("tan", functionTan);
+        registerFunction("sec", functionSec);
+        registerFunction("csc", functionCsc);
+        registerFunction("cot", functionCot);
+    }
+
+    @Override
+    public void onDisable() {
+
+    }
+}

src/main/java/org/nwapw/abacus/tree/NumberReducer.java

@@ -0,0 +1,54 @@
+package org.nwapw.abacus.tree;
+
+import org.nwapw.abacus.Abacus;
+import org.nwapw.abacus.function.Function;
+import org.nwapw.abacus.number.NumberInterface;
+
+/**
+ * A reducer implementation that turns a tree into a single number.
+ * This is not always guaranteed to work.
+ */
+public class NumberReducer implements Reducer<NumberInterface> {
+
+    /**
+     * The plugin manager from which to draw the functions.
+     */
+    private Abacus abacus;
+
+    /**
+     * Creates a new number reducer.
+     *
+     * @param abacus the calculator instance.
+     */
+    public NumberReducer(Abacus abacus) {
+        this.abacus = abacus;
+    }
+
+    @Override
+    public NumberInterface reduceNode(TreeNode node, Object... children) {
+        if (node instanceof NumberNode) {
+            return ((NumberNode) node).getNumber();
+        } else if (node instanceof BinaryNode) {
+            NumberInterface left = (NumberInterface) children[0];
+            NumberInterface right = (NumberInterface) children[1];
+            Function function = abacus.getPluginManager().operatorFor(((BinaryNode) node).getOperation()).getFunction();
+            if (function == null) return null;
+            return function.apply(left, right);
+        } else if (node instanceof UnaryNode) {
+            NumberInterface child = (NumberInterface) children[0];
+            Function functionn = abacus.getPluginManager().operatorFor(((UnaryNode) node).getOperation()).getFunction();
+            if (functionn == null) return null;
+            return functionn.apply(child);
+        } else if (node instanceof FunctionNode) {
+            NumberInterface[] convertedChildren = new NumberInterface[children.length];
+            for (int i = 0; i < convertedChildren.length; i++) {
+                convertedChildren[i] = (NumberInterface) children[i];
+            }
+            Function function = abacus.getPluginManager().functionFor(((FunctionNode) node).getFunction());
+            if (function == null) return null;
+            return function.apply(convertedChildren);
+        }
+        return null;
+    }
+
+}

src/main/java/org/nwapw/abacus/tree/Reducer.java

@@ -0,0 +1,19 @@
+package org.nwapw.abacus.tree;
+
+/**
+ * Interface used to reduce a tree into a single value.
+ *
+ * @param <T> the value to reduce into.
+ */
+public interface Reducer<T> {
+
+    /**
+     * Reduces the given tree into a single value of type T.
+     *
+     * @param node     the node being passed in to be reduced.
+     * @param children the already-reduced children of this node.
+     * @return the resulting value from the reduce.
+     */
+    public T reduceNode(TreeNode node, Object... children);
+
+}

src/main/java/org/nwapw/abacus/tree/TokenType.java

@@ -7,8 +7,7 @@ package org.nwapw.abacus.tree;
 public enum TokenType {
 
     INTERNAL_FUNCTION_END(-1),
-    ANY(0), WHITESPACE(1), COMMA(2), VARIABLE(3), OP(4), TREE_VALUE_OP(4),
+    ANY(0), WHITESPACE(1), COMMA(2), OP(3), NUM(4), FUNCTION(5), OPEN_PARENTH(6), CLOSE_PARENTH(7);
-    NUM(5), FUNCTION(6), TREE_VALUE_FUNCTION(6), OPEN_PARENTH(7), CLOSE_PARENTH(7);
 
     /**
      * The priority by which this token gets sorted.

src/main/java/org/nwapw/abacus/window/HistoryTableModel.java

@@ -0,0 +1,106 @@
+package org.nwapw.abacus.window;
+
+import org.nwapw.abacus.tree.TreeNode;
+
+import javax.swing.table.AbstractTableModel;
+import java.util.ArrayList;
+import java.util.List;
+
+/**
+ * A table model to store data about the history of inputs
+ * in the calculator.
+ */
+public class HistoryTableModel extends AbstractTableModel {
+
+    /**
+     * Static array used to get the column names.
+     */
+    public static final String[] COLUMN_NAMES = {
+            "Input",
+            "Parsed Input",
+            "Output"
+    };
+
+    /**
+     * Static array used to get the class of each column.
+     */
+    public static final Class[] CLASS_TYPES = {
+            String.class,
+            TreeNode.class,
+            String.class
+    };
+    /**
+     * The list of entries.
+     */
+    List<HistoryEntry> entries;
+
+    /**
+     * Creates a new empty history table model
+     */
+    public HistoryTableModel() {
+        entries = new ArrayList<>();
+    }
+
+    /**
+     * Adds an entry to the model.
+     *
+     * @param entry the entry to add.
+     */
+    public void addEntry(HistoryEntry entry) {
+        entries.add(entry);
+    }
+
+    @Override
+    public int getRowCount() {
+        return entries.size();
+    }
+
+    @Override
+    public int getColumnCount() {
+        return 3;
+    }
+
+    @Override
+    public String getColumnName(int columnIndex) {
+        return COLUMN_NAMES[columnIndex];
+    }
+
+    @Override
+    public Class<?> getColumnClass(int columnIndex) {
+        return CLASS_TYPES[columnIndex];
+    }
+
+    @Override
+    public boolean isCellEditable(int rowIndex, int columnIndex) {
+        return false;
+    }
+
+    @Override
+    public Object getValueAt(int rowIndex, int columnIndex) {
+        return entries.get(rowIndex).nthValue(columnIndex);
+    }
+
+    /**
+     * Class used specifically to hold data about
+     * the previous entries into the calculator.
+     */
+    public static class HistoryEntry {
+        public String input;
+        public TreeNode parsedInput;
+        public String output;
+
+        public HistoryEntry(String input, TreeNode parsedInput, String output) {
+            this.input = input;
+            this.parsedInput = parsedInput;
+            this.output = output;
+        }
+
+        Object nthValue(int n) {
+            if (n == 0) return input;
+            if (n == 1) return parsedInput;
+            if (n == 2) return output;
+            return null;
+        }
+    }
+
+}

src/main/java/org/nwapw/abacus/window/Window.java

@@ -0,0 +1,255 @@
+package org.nwapw.abacus.window;
+
+import org.nwapw.abacus.Abacus;
+import org.nwapw.abacus.number.NumberInterface;
+import org.nwapw.abacus.tree.TreeNode;
+
+import javax.swing.*;
+import java.awt.*;
+import java.awt.datatransfer.StringSelection;
+import java.awt.event.ActionListener;
+import java.awt.event.MouseAdapter;
+import java.awt.event.MouseEvent;
+
+/**
+ * The main UI window for the calculator.
+ */
+public class Window extends JFrame {
+
+    private static final String CALC_STRING = "Calculate";
+    private static final String SYNTAX_ERR_STRING = "Syntax Error";
+    private static final String EVAL_ERR_STRING = "Evaluation Error";
+    private static final String NUMBER_SYSTEM_LABEL = "Number Type:";
+    private static final String FUNCTION_LABEL = "Functions:";
+
+    /**
+     * Array of Strings to which the "calculate" button's text
+     * changes. For instance, in the graph tab, the name will
+     * be "Graph" and not "Calculate".
+     */
+    private static final String[] BUTTON_NAMES = {
+            CALC_STRING,
+            CALC_STRING
+    };
+
+    /**
+     * Array of booleans that determine whether the input
+     * field and the input button are enabled at a particular
+     * index.
+     */
+    private static boolean[] INPUT_ENABLED = {
+            true,
+            false
+    };
+
+    /**
+     * The instance of the Abacus class, used
+     * for interaction with plugins and configuration.
+     */
+    private Abacus abacus;
+    /**
+     * The last output by the calculator.
+     */
+    private String lastOutput;
+
+    /**
+     * The tabbed pane that separates calculator contexts.
+     */
+    private JTabbedPane pane;
+
+    /**
+     * The panel where the output occurs.
+     */
+    private JPanel calculationPanel;
+    /**
+     * The text area reserved for the last output.
+     */
+    private JTextArea lastOutputArea;
+    /**
+     * The table used for storing history results.
+     */
+    private JTable historyTable;
+    /**
+     * The table model used for managing history.
+     */
+    private HistoryTableModel historyModel;
+    /**
+     * The scroll pane for the history area.
+     */
+    private JScrollPane historyScroll;
+
+    /**
+     * The panel where the input occurs.
+     */
+    private JPanel inputPanel;
+    /**
+     * The input text field.
+     */
+    private JTextField inputField;
+    /**
+     * The "submit" button.
+     */
+    private JButton inputEnterButton;
+
+    /**
+     * The side panel for separate configuration.
+     */
+    private JPanel settingsPanel;
+    /**
+     * Panel for elements relating to number
+     * system selection.
+     */
+    private JPanel numberSystemPanel;
+    /**
+     * The possible list of number systems.
+     */
+    private JComboBox<String> numberSystemList;
+    /**
+     * The panel for elements relating to
+     * function selection.
+     */
+    private JPanel functionSelectPanel;
+    /**
+     * The list of functions available to the user.
+     */
+    private JComboBox<String> functionList;
+
+    /**
+     * Action listener that causes the input to be evaluated.
+     */
+    private ActionListener evaluateListener = (event) -> {
+        TreeNode parsedExpression = abacus.parseString(inputField.getText());
+        if (parsedExpression == null) {
+            lastOutputArea.setText(SYNTAX_ERR_STRING);
+            return;
+        }
+        NumberInterface numberInterface = abacus.evaluateTree(parsedExpression);
+        if (numberInterface == null) {
+            lastOutputArea.setText(EVAL_ERR_STRING);
+            return;
+        }
+        lastOutput = numberInterface.toString();
+        historyModel.addEntry(new HistoryTableModel.HistoryEntry(inputField.getText(), parsedExpression, lastOutput));
+        historyTable.invalidate();
+        lastOutputArea.setText(lastOutput);
+        inputField.setText("");
+    };
+
+    /**
+     * Array of listeners that tell the input button how to behave
+     * at a given input tab.
+     */
+    private ActionListener[] listeners = {
+            evaluateListener,
+            null
+    };
+
+    /**
+     * Creates a new window with the given manager.
+     *
+     * @param abacus the calculator instance to interact with other components.
+     */
+    public Window(Abacus abacus) {
+        this();
+        this.abacus = abacus;
+    }
+
+    /**
+     * Creates a new window.
+     */
+    private Window() {
+        super();
+
+        lastOutput = "";
+
+        setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);
+        setSize(320, 480);
+
+        inputField = new JTextField();
+        inputEnterButton = new JButton(CALC_STRING);
+
+        inputPanel = new JPanel();
+        inputPanel.setLayout(new BorderLayout());
+        inputPanel.add(inputField, BorderLayout.CENTER);
+        inputPanel.add(inputEnterButton, BorderLayout.SOUTH);
+
+        historyModel = new HistoryTableModel();
+        historyTable = new JTable(historyModel);
+        historyScroll = new JScrollPane(historyTable);
+        lastOutputArea = new JTextArea(lastOutput);
+        lastOutputArea.setEditable(false);
+
+        calculationPanel = new JPanel();
+        calculationPanel.setLayout(new BorderLayout());
+        calculationPanel.add(historyScroll, BorderLayout.CENTER);
+        calculationPanel.add(lastOutputArea, BorderLayout.SOUTH);
+
+        numberSystemList = new JComboBox<>();
+
+        numberSystemPanel = new JPanel();
+        numberSystemPanel.setAlignmentX(Component.LEFT_ALIGNMENT);
+        numberSystemPanel.setLayout(new FlowLayout());
+        numberSystemPanel.add(new JLabel(NUMBER_SYSTEM_LABEL));
+        numberSystemPanel.add(numberSystemList);
+        numberSystemPanel.setMaximumSize(numberSystemPanel.getPreferredSize());
+
+        functionList = new JComboBox<>();
+
+        functionSelectPanel = new JPanel();
+        functionSelectPanel.setAlignmentX(Component.LEFT_ALIGNMENT);
+        functionSelectPanel.setLayout(new FlowLayout());
+        functionSelectPanel.add(new JLabel(FUNCTION_LABEL));
+        functionSelectPanel.add(functionList);
+        functionSelectPanel.setMaximumSize(functionSelectPanel.getPreferredSize());
+
+        settingsPanel = new JPanel();
+        settingsPanel.setAlignmentX(Component.LEFT_ALIGNMENT);
+        settingsPanel.setLayout(new BoxLayout(settingsPanel, BoxLayout.PAGE_AXIS));
+        settingsPanel.add(numberSystemPanel);
+        settingsPanel.add(functionSelectPanel);
+
+        pane = new JTabbedPane();
+        pane.add("Calculator", calculationPanel);
+        pane.add("Settings", settingsPanel);
+        pane.addChangeListener(e -> {
+            int selectionIndex = pane.getSelectedIndex();
+            boolean enabled = INPUT_ENABLED[selectionIndex];
+            ActionListener listener = listeners[selectionIndex];
+            inputEnterButton.setText(BUTTON_NAMES[selectionIndex]);
+            inputField.setEnabled(enabled);
+            inputEnterButton.setEnabled(enabled);
+
+            for (ActionListener removingListener : inputEnterButton.getActionListeners()) {
+                inputEnterButton.removeActionListener(removingListener);
+                inputField.removeActionListener(removingListener);
+            }
+            if (listener != null) {
+                inputEnterButton.addActionListener(listener);
+                inputField.addActionListener(listener);
+            }
+        });
+        add(pane, BorderLayout.CENTER);
+        add(inputPanel, BorderLayout.SOUTH);
+
+        inputEnterButton.addActionListener(evaluateListener);
+        inputField.addActionListener(evaluateListener);
+        historyTable.addMouseListener(new MouseAdapter() {
+            @Override
+            public void mouseClicked(MouseEvent e) {
+                Point clickPoint = e.getPoint();
+                if (e.getClickCount() == 2) {
+                    int row = historyTable.rowAtPoint(clickPoint);
+                    int column = historyTable.columnAtPoint(clickPoint);
+                    String toCopy = historyTable.getValueAt(row, column).toString();
+                    Toolkit.getDefaultToolkit().getSystemClipboard().setContents(new StringSelection(toCopy), null);
+                }
+            }
+        });
+    }
+
+    @Override
+    public void setVisible(boolean b) {
+        super.setVisible(b);
+        if (b) inputField.requestFocusInWindow();
+    }
+}

src/main/kotlin/org/nwapw/abacus/function/Operator.kt

@@ -3,11 +3,12 @@ package org.nwapw.abacus.function
 /**
  * A single operator that can be used by Abacus.
  *
- * This is a class that holds the information about a single operator, such as a plus or minus.
+ * This is a data class that holds the information about a single operator, such as a plus or minus.
  *
  * @param associativity the associativity of this operator, used for order of operations;.
  * @param type the type of this operator, used for parsing (infix / prefix / postfix and binary / unary)
  * @param precedence the precedence of this operator, used for order of operations.
+ * @param function the function this operator applies to its arguments.
  */
-open class Operator(val associativity: OperatorAssociativity, val type: OperatorType,
+data class Operator(val associativity: OperatorAssociativity, val type: OperatorType,
-                    val precedence: Int)
+                    val precedence: Int, val function: Function)

src/main/kotlin/org/nwapw/abacus/fx/HistoryModel.kt

@@ -14,7 +14,7 @@ import javafx.beans.property.SimpleStringProperty
  * @param parsed the parsed version of the input.
  * @param output the output string.
  */
-class HistoryModel(input: String, parsed: String, output: String) {
+class HistoryModel(input: String, parsed: String, output: String){
 
     /**
      * The property that holds the input.

src/main/kotlin/org/nwapw/abacus/fx/ToggleablePlugin.kt

@@ -12,7 +12,7 @@ import javafx.beans.property.SimpleBooleanProperty
  * @param className the name of the class that this model concerns.
  * @param enabled whether or not the model should start enabled.
  */
-class ToggleablePlugin(val className: String, enabled: Boolean) {
+class ToggleablePlugin (val className: String, enabled: Boolean) {
 
     /**
      * The property used to interact with JavaFX components.

src/main/kotlin/org/nwapw/abacus/tree/BinaryNode.kt

@@ -11,10 +11,16 @@ package org.nwapw.abacus.tree
  * @param left the left node.
  * @param right the right node.
  */
-abstract class BinaryNode(val operation: String, val left: TreeNode, val right: TreeNode) : TreeNode() {
+data class BinaryNode(val operation: String, val left: TreeNode? = null, val right: TreeNode?) : TreeNode() {
+
+    override fun <T : Any> reduce(reducer: Reducer<T>): T? {
+        val leftReduce = left?.reduce(reducer) ?: return null
+        val rightReduce = right?.reduce(reducer) ?: return null
+        return reducer.reduceNode(this, leftReduce, rightReduce)
+    }
 
     override fun toString(): String {
-        return "(" + left.toString() + operation + right.toString() + ")"
+        return "(" + (left?.toString() ?: "null") + operation + (right?.toString() ?: "null") + ")"
     }
 
 }

src/main/kotlin/org/nwapw/abacus/tree/FunctionNode.kt

@@ -0,0 +1,52 @@
+package org.nwapw.abacus.tree
+
+/**
+ * A tree node that holds a function call.
+ *
+ * The function call node can hold any number of children, and passes the to the appropriate reducer,
+ * but that is its sole purpose.
+ *
+ * @param function the function string.
+ */
+data class FunctionNode(val function: String) : TreeNode() {
+
+    /**
+     * List of function parameters added to this node.
+     */
+    val children: MutableList<TreeNode> = mutableListOf()
+
+    override fun <T : Any> reduce(reducer: Reducer<T>): T? {
+        val children = Array<Any?>(children.size, { children[it].reduce(reducer) ?: return null; })
+        return reducer.reduceNode(this, *children)
+    }
+
+    override fun toString(): String {
+        val buffer = StringBuffer()
+        buffer.append(function)
+        buffer.append('(')
+        for (i in 0 until children.size) {
+            buffer.append(children[i].toString())
+            buffer.append(if (i == children.size - 1) ")" else ",")
+        }
+        return buffer.toString()
+    }
+
+    /**
+     * Appends a child to this node's list of children.
+     *
+     * @node the node to append.
+     */
+    fun appendChild(node: TreeNode){
+        children.add(node)
+    }
+
+    /**
+     * Prepends a child to this node's list of children.
+     *
+     * @node the node to prepend.
+     */
+    fun prependChild(node: TreeNode){
+        children.add(0, node)
+    }
+
+}

src/main/kotlin/org/nwapw/abacus/tree/NumberNode.kt

@@ -1,5 +1,7 @@
 package org.nwapw.abacus.tree
 
+import org.nwapw.abacus.number.NumberInterface
+
 /**
  * A tree node that holds a single number value.
  *
@@ -8,14 +10,14 @@ package org.nwapw.abacus.tree
  *
  * @number the number value of this node.
  */
-class NumberNode(val number: String) : TreeNode() {
+data class NumberNode(val number: NumberInterface) : TreeNode() {
 
-    override fun <T : Any> reduce(reducer: Reducer<T>): T {
+    override fun <T : Any> reduce(reducer: Reducer<T>): T? {
         return reducer.reduceNode(this)
     }
 
     override fun toString(): String {
-        return number
+        return number.toString()
     }
 
 }

src/main/kotlin/org/nwapw/abacus/tree/TreeNode.kt

@@ -5,6 +5,6 @@ package org.nwapw.abacus.tree
  */
 abstract class TreeNode {
 
-    abstract fun <T : Any> reduce(reducer: Reducer<T>): T
+    abstract fun <T: Any> reduce(reducer: Reducer<T>) : T?
 
 }