Merge branch 'master' into new_image

Implement tree operators and functions.

build.gradle

@@ -1,20 +1,29 @@
-plugins {
+buildscript {
-    id 'java'
+    ext.kotlin_version = '1.1.3'
-    id 'application'
+    ext.dokka_version = '0.9.15'
-    id 'org.jetbrains.kotlin.jvm' version '1.1.3'
-}
-apply plugin: 'java'
-apply plugin: 'application'
 
-repositories {
+    repositories {
-  mavenCentral()
+        jcenter()
+    }
+
+    dependencies {
+        classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:$kotlin_version"
+        classpath "org.jetbrains.dokka:dokka-gradle-plugin:$dokka_version"
+    }
 }
 
-dependencies {
+subprojects {
-    compile 'com.moandjiezana.toml:toml4j:0.7.1'
+
-    compile "org.jetbrains.kotlin:kotlin-stdlib-jre8"
+    apply plugin: 'java'
-    testCompile 'junit:junit:4.12'
+    apply plugin: 'kotlin'
+    apply plugin: 'org.jetbrains.dokka'
+
+    repositories {
+        mavenCentral()
+    }
+
+    dependencies {
+        compile "org.jetbrains.kotlin:kotlin-stdlib-jre7:1.1.3"
+    }
 }
 
-mainClassName = 'org.nwapw.abacus.Abacus'
-

core/build.gradle

@@ -0,0 +1,4 @@
+dependencies {
+    compile 'com.moandjiezana.toml:toml4j:0.7.1'
+    testCompile 'junit:junit:4.12'
+}

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

@@ -1,7 +1,6 @@
 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;
@@ -54,17 +53,13 @@ public class Abacus {
         numberReducer = new NumberReducer(this);
         this.configuration = new Configuration(configuration);
         LexerTokenizer lexerTokenizer = new LexerTokenizer();
-        ShuntingYardParser shuntingYardParser = new ShuntingYardParser(this);
+        ShuntingYardParser shuntingYardParser = new ShuntingYardParser();
         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.
      *

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

@@ -48,7 +48,7 @@ public class Configuration {
      *
      * @param copyFrom the configuration to copy.
      */
-    public Configuration(Configuration copyFrom){
+    public Configuration(Configuration copyFrom) {
         copyFrom(copyFrom);
     }
 
@@ -106,7 +106,7 @@ public class Configuration {
      *
      * @return the string that represents this configuration.
      */
-    public String asTomlString(){
+    public String asTomlString() {
         return TOML_WRITER.write(this);
     }
 

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

@@ -0,0 +1,11 @@
+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/number/ComputationInterruptedException.java

@@ -9,7 +9,7 @@ public class ComputationInterruptedException extends RuntimeException {
     /**
      * Creates a new exception of this type.
      */
-    public ComputationInterruptedException(){
+    public ComputationInterruptedException() {
         super("Computation interrupted by user.");
     }
 

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

@@ -129,7 +129,7 @@ public class NaiveNumber extends NumberInterface {
     }
 
     @Override
-    public NumberInterface getMaxError(){
+    public NumberInterface getMaxError() {
         return new NaiveNumber(Math.pow(10, -18));
     }
 }

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

@@ -9,10 +9,11 @@ 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.
      *
@@ -38,7 +39,7 @@ public abstract class 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);
     }
@@ -61,7 +62,7 @@ public abstract class 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);
     }
@@ -84,7 +85,7 @@ public abstract class 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);
     }
@@ -107,7 +108,7 @@ public abstract class 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);
     }
@@ -129,7 +130,7 @@ public abstract class NumberInterface {
      *
      * @return the new instance.
      */
-    public final NumberInterface negate(){
+    public final NumberInterface negate() {
         checkInterrupted();
         return negateInternal();
     }
@@ -150,7 +151,7 @@ public abstract class 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);
     }
@@ -184,7 +185,7 @@ public abstract class NumberInterface {
      *
      * @return the least integer bigger or equal to the number.
      */
-    public final NumberInterface ceiling(){
+    public final NumberInterface ceiling() {
         checkInterrupted();
         return ceilingInternal();
     }
@@ -203,7 +204,7 @@ public abstract class NumberInterface {
      *
      * @return the greatest int smaller than or equal to the number.
      */
-    public final NumberInterface floor(){
+    public final NumberInterface floor() {
         checkInterrupted();
         return floorInternal();
     }
@@ -219,9 +220,10 @@ public abstract class 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();
     }
@@ -260,6 +262,7 @@ public abstract class NumberInterface {
     /**
      * 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();

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

@@ -35,7 +35,7 @@ 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.
@@ -129,7 +129,7 @@ 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;
@@ -166,7 +166,7 @@ public class PreciseNumber extends NumberInterface {
     }
 
     @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()));
     }
 }

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

@@ -34,6 +34,7 @@ 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);
         }};
@@ -49,9 +50,15 @@ 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
@@ -59,9 +66,15 @@ 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);
+        }
     }
 
 }

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

@@ -1,6 +1,5 @@
 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;
@@ -17,10 +16,6 @@ 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.
      */
@@ -35,12 +30,9 @@ public class ShuntingYardParser implements Parser<Match<TokenType>>, PluginListe
     private Map<String, OperatorType> typeMap;
 
     /**
-     * Creates a new Shunting Yard parser with the given Abacus instance.
+     * Creates a new Shunting Yard parser.
-     *
-     * @param abacus the abacus instance.
      */
-    public ShuntingYardParser(Abacus abacus) {
+    public ShuntingYardParser() {
-        this.abacus = abacus;
         precedenceMap = new HashMap<>();
         associativityMap = new HashMap<>();
         typeMap = new HashMap<>();
@@ -61,12 +53,12 @@ public class ShuntingYardParser implements Parser<Match<TokenType>>, PluginListe
             Match<TokenType> match = from.remove(0);
             previousType = matchType;
             matchType = match.getType();
-            if (matchType == TokenType.NUM) {
+            if (matchType == TokenType.NUM || matchType == TokenType.VARIABLE) {
                 output.add(match);
-            } else if (matchType == TokenType.FUNCTION) {
+            } else if (matchType == TokenType.FUNCTION || matchType == TokenType.TREE_VALUE_FUNCTION) {
                 output.add(new Match<>("", TokenType.INTERNAL_FUNCTION_END));
                 tokenStack.push(match);
-            } else if (matchType == TokenType.OP) {
+            } else if (matchType == TokenType.OP || matchType == TokenType.TREE_VALUE_OP) {
                 String tokenString = match.getContent();
                 OperatorType type = typeMap.get(tokenString);
                 int precedence = precedenceMap.get(tokenString);
@@ -78,7 +70,7 @@ public class ShuntingYardParser implements Parser<Match<TokenType>>, PluginListe
                 }
 
                 if (tokenString.equals("-") && (previousType == null || previousType == TokenType.OP ||
-                        previousType == TokenType.OPEN_PARENTH)) {
+                        previousType == TokenType.TREE_VALUE_OP || previousType == TokenType.OPEN_PARENTH)) {
                     from.add(0, new Match<>("`", TokenType.OP));
                     continue;
                 }
@@ -86,9 +78,12 @@ 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 || otherMatchType == TokenType.FUNCTION)) break;
+                    if (!(otherMatchType == TokenType.OP ||
+                            otherMatchType == TokenType.TREE_VALUE_OP ||
+                            otherMatchType == TokenType.FUNCTION ||
+                            otherMatchType == TokenType.TREE_VALUE_FUNCTION)) break;
 
-                    if (otherMatchType == TokenType.OP) {
+                    if (otherMatchType == TokenType.OP || otherMatchType == TokenType.TREE_VALUE_OP) {
                         int otherPrecedence = precedenceMap.get(otherMatch.getContent());
                         if (otherPrecedence < precedence ||
                                 (associativity == OperatorAssociativity.RIGHT && otherPrecedence == precedence)) {
@@ -113,7 +108,10 @@ public class ShuntingYardParser implements Parser<Match<TokenType>>, PluginListe
         while (!tokenStack.empty()) {
             Match<TokenType> match = tokenStack.peek();
             TokenType newMatchType = match.getType();
-            if (!(newMatchType == TokenType.OP || newMatchType == TokenType.FUNCTION)) return null;
+            if (!(newMatchType == TokenType.OP ||
+                    newMatchType == TokenType.TREE_VALUE_OP ||
+                    newMatchType == TokenType.FUNCTION ||
+                    newMatchType == TokenType.TREE_VALUE_FUNCTION)) return null;
             output.add(tokenStack.pop());
         }
         return output;
@@ -129,28 +127,43 @@ 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) {
+        if (matchType == TokenType.OP || matchType == TokenType.TREE_VALUE_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;
-                else return new BinaryNode(operator, left, right);
+                if(matchType == TokenType.OP) {
+                    return new NumberBinaryNode(operator, left, right);
+                } else {
+                    return new TreeValueBinaryNode(operator, left, right);
+                }
             } else {
                 TreeNode applyTo = constructRecursive(matches);
                 if (applyTo == null) return null;
-                else return new UnaryNode(operator, applyTo);
+                if(matchType == TokenType.OP){
+                    return new NumberUnaryNode(operator, applyTo);
+                } else {
+                    return new TreeValueUnaryNode(operator, applyTo);
+                }
             }
         } else if (matchType == TokenType.NUM) {
-            return new NumberNode(abacus.numberFromString(match.getContent()));
+            return new NumberNode(match.getContent());
-        } else if (matchType == TokenType.FUNCTION) {
+        } else if (matchType == TokenType.VARIABLE) {
+            return new VariableNode(match.getContent());
+        } else if (matchType == TokenType.FUNCTION || matchType == TokenType.TREE_VALUE_FUNCTION) {
             String functionName = match.getContent();
-            FunctionNode node = new FunctionNode(functionName);
+            CallNode node;
+            if(matchType == TokenType.FUNCTION){
+                node = new FunctionNode(functionName);
+            } else {
+                node = new TreeValueFunctionNode(functionName);
+            }
             while (!matches.isEmpty() && matches.get(0).getType() != TokenType.INTERNAL_FUNCTION_END) {
                 TreeNode argument = constructRecursive(matches);
                 if (argument == null) return null;
-                node.prependChild(argument);
+                node.getChildren().add(0, argument);
             }
             if (matches.isEmpty()) return null;
             matches.remove(0);
@@ -162,7 +175,7 @@ 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;
@@ -176,6 +189,12 @@ 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

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

@@ -1,15 +1,8 @@
 package org.nwapw.abacus.plugin;
 
-import org.nwapw.abacus.function.Documentation;
+import org.nwapw.abacus.function.*;
-import org.nwapw.abacus.function.DocumentationType;
-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
@@ -69,10 +62,21 @@ public abstract class Plugin {
      * @param name       the name to register by.
      * @param toRegister the function implementation.
      */
-    protected final void registerFunction(String name, Function toRegister) {
+    protected final void registerFunction(String name, NumberFunction 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
@@ -81,10 +85,22 @@ public abstract class Plugin {
      * @param name     the name of the operator.
      * @param operator the operator to register.
      */
-    protected final void registerOperator(String name, Operator operator) {
+    protected final void registerOperator(String name, NumberOperator 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.
@@ -99,9 +115,10 @@ public abstract class Plugin {
     /**
      * 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){
+    protected final void registerDocumentation(Documentation documentation) {
         manager.registerDocumentation(documentation);
     }
 
@@ -113,10 +130,22 @@ 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 Function functionFor(String name) {
+    protected final NumberFunction 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
@@ -125,10 +154,22 @@ 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 Operator operatorFor(String name) {
+    protected final NumberOperator 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
@@ -148,7 +189,7 @@ public abstract class Plugin {
      * @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){
+    protected final Documentation documentationFor(String name, DocumentationType type) {
         return manager.documentationFor(name, type);
     }
 

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

@@ -1,14 +1,14 @@
 package org.nwapw.abacus.plugin;
 
 import org.nwapw.abacus.Abacus;
-import org.nwapw.abacus.function.Documentation;
+import org.nwapw.abacus.function.*;
-import org.nwapw.abacus.function.DocumentationType;
-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.*;
+import java.util.HashMap;
+import java.util.HashSet;
+import java.util.Map;
+import java.util.Set;
 
 /**
  * A class that controls instances of plugins, allowing for them
@@ -27,11 +27,19 @@ public class PluginManager {
     /**
      * The map of functions registered by the plugins.
      */
-    private Map<String, Function> registeredFunctions;
+    private Map<String, NumberFunction> 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, Operator> registeredOperators;
+    private Map<String, NumberOperator> 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.
      */
@@ -69,7 +77,9 @@ 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<>();
@@ -79,82 +89,130 @@ public class PluginManager {
 
     /**
      * Registers a function under the given name.
-     * @param name the name of the function.
+     *
+     * @param name     the name of the function.
      * @param function the function to register.
      */
-    public void registerFunction(String name, Function function){
+    public void registerFunction(String name, NumberFunction 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 name     the name of the operator.
      * @param operator the operator to register.
      */
-    public void registerOperator(String name, Operator operator){
+    public void registerOperator(String name, NumberOperator 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 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);
     }
 
     /**
      * 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){
+    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 Function functionFor(String name){
+    public NumberFunction 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 Operator operatorFor(String name){
+    public NumberOperator 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){
+    public Documentation documentationFor(String name, DocumentationType type) {
         Documentation toReturn = null;
-        for(Documentation entry : registeredDocumentation){
+        for (Documentation entry : registeredDocumentation) {
-            if(entry.getCodeName().equals(name) && entry.getType() == type) {
+            if (entry.getCodeName().equals(name) && entry.getType() == type) {
                 toReturn = entry;
                 break;
             }
         }
-        if(toReturn == null){
+        if (toReturn == null) {
             toReturn = new Documentation(name, "", "", "", type);
             registerDocumentation(toReturn);
         }
@@ -170,9 +228,9 @@ public class PluginManager {
     public NumberImplementation interfaceImplementationFor(Class<? extends NumberInterface> name) {
         if (cachedInterfaceImplementations.containsKey(name)) return cachedInterfaceImplementations.get(name);
         NumberImplementation toReturn = null;
-        for(String key : registeredNumberImplementations.keySet()){
+        for (String key : registeredNumberImplementations.keySet()) {
             NumberImplementation implementation = registeredNumberImplementations.get(key);
-            if(implementation.getImplementation() == name) {
+            if (implementation.getImplementation() == name) {
                 toReturn = implementation;
                 break;
             }
@@ -226,10 +284,11 @@ 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){
+    public void removeClass(Class<? extends Plugin> toRemove) {
-        if(!loadedPluginClasses.contains(toRemove)) return;
+        if (!loadedPluginClasses.contains(toRemove)) return;
         plugins.removeIf(plugin -> plugin.getClass() == toRemove);
         loadedPluginClasses.remove(toRemove);
     }
@@ -237,7 +296,7 @@ public class PluginManager {
     /**
      * Removes all plugins from this plugin manager.
      */
-    public void removeAll(){
+    public void removeAll() {
         loadedPluginClasses.clear();
         plugins.clear();
     }
@@ -265,7 +324,9 @@ public class PluginManager {
             plugin.disable();
         }
         registeredFunctions.clear();
+        registeredTreeValueFunctions.clear();
         registeredOperators.clear();
+        registeredTreeValueOperators.clear();
         registeredNumberImplementations.clear();
         registeredDocumentation.clear();
         cachedInterfaceImplementations.clear();
@@ -290,6 +351,15 @@ 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.
      *
@@ -299,6 +369,15 @@ 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.
      *

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

@@ -1,19 +1,12 @@
 package org.nwapw.abacus.plugin;
 
 import org.nwapw.abacus.function.*;
-import org.nwapw.abacus.lexing.pattern.Match;
 import org.nwapw.abacus.number.NaiveNumber;
 import org.nwapw.abacus.number.NumberInterface;
 import org.nwapw.abacus.number.PreciseNumber;
-import org.nwapw.abacus.parsing.Parser;
-import org.nwapw.abacus.parsing.ShuntingYardParser;
-import org.nwapw.abacus.tree.TokenType;
-import org.nwapw.abacus.tree.TreeNode;
 
 import java.util.ArrayList;
-import java.util.Date;
 import java.util.HashMap;
-import java.util.List;
 import java.util.function.BiFunction;
 
 /**
@@ -22,104 +15,159 @@ import java.util.function.BiFunction;
  */
 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() {
+    public static final NumberOperator OP_ADD = new NumberOperator(OperatorAssociativity.LEFT, OperatorType.BINARY_INFIX, 0) {
         @Override
-        protected boolean matchesParams(NumberInterface[] params) {
+        public 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) {
+        public NumberInterface applyInternal(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(NumberInterface[] params) {
+            return params.length == 2;
+        }
+
+        @Override
+        public 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() {
+    public static final NumberOperator OP_NEGATE = new NumberOperator(OperatorAssociativity.LEFT, OperatorType.UNARY_PREFIX, 0) {
         @Override
-        protected boolean matchesParams(NumberInterface[] params) {
+        public boolean matchesParams(NumberInterface[] params) {
             return params.length == 1;
         }
 
         @Override
-        protected NumberInterface applyInternal(NumberInterface[] params) {
+        public 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() {
+    public static final NumberOperator OP_MULTIPLY = new NumberOperator(OperatorAssociativity.LEFT, OperatorType.BINARY_INFIX, 1) {
         @Override
-        protected boolean matchesParams(NumberInterface[] params) {
+        public boolean matchesParams(NumberInterface[] params) {
-            return params.length >= 1;
+            return params.length == 2;
         }
 
         @Override
-        protected NumberInterface applyInternal(NumberInterface[] params) {
+        public NumberInterface applyInternal(NumberInterface[] params) {
-            NumberInterface product = params[0];
+            return params[0].multiply(params[1]);
-            for (int i = 1; i < params.length; i++) {
-                product = product.multiply(params[i]);
-            }
-            return product;
         }
-    });
+    };
+    /**
+     * 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 square root function.
+     */
+    public static final NumberFunction FUNCTION_SQRT = new NumberFunction() {
+        @Override
+        public boolean matchesParams(NumberInterface[] params) {
+            return params.length == 1;
+        }
+
+        @Override
+        public NumberInterface applyInternal(NumberInterface[] params) {
+            return OP_CARET.apply(params[0], ((new NaiveNumber(0.5)).promoteTo(params[0].getClass())));
+        }
+    };
+    /**
+     * 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 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);
+        }
+    };
+    /**
+     * Stores objects of NumberInterface with integer values for reuse.
+     */
+    private final static HashMap<Class<? extends NumberInterface>, HashMap<Integer, NumberInterface>> integerValues = new HashMap<>();
     /**
      * The division operator, /
      */
-    public static final Operator OP_DIVIDE = new Operator(OperatorAssociativity.LEFT, OperatorType.BINARY_INFIX, 1, new Function() {
+    public static final NumberOperator OP_DIVIDE = new NumberOperator(OperatorAssociativity.LEFT, OperatorType.BINARY_INFIX, 1) {
         @Override
-        protected boolean matchesParams(NumberInterface[] params) {
+        public boolean matchesParams(NumberInterface[] params) {
             return params.length == 2 && params[1].compareTo(fromInt(params[0].getClass(), 0)) != 0;
         }
 
         @Override
-        protected NumberInterface applyInternal(NumberInterface[] params) {
+        public 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() {
+    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
-        protected boolean matchesParams(NumberInterface[] params) {
+        public boolean matchesParams(NumberInterface[] params) {
             return params.length == 1
                     && params[0].fractionalPart().compareTo(fromInt(params[0].getClass(), 0)) == 0
                     && params[0].signum() >= 0;
         }
 
         @Override
-        protected NumberInterface applyInternal(NumberInterface[] params) {
+        public NumberInterface applyInternal(NumberInterface[] params) {
             if (params[0].signum() == 0) {
                 return fromInt(params[0].getClass(), 1);
             }
@@ -137,77 +185,77 @@ public class StandardPlugin extends Plugin {
                     storedList.get(params[0].getClass()).add(NaiveNumber.ONE.promoteTo(params[0].getClass()));
                 }*/
         }
-    });
+    };
     /**
      * The permutation operator.
      */
-    public static final Operator OP_NPR = new Operator(OperatorAssociativity.RIGHT, OperatorType.BINARY_INFIX, 0, new Function() {
+    public static final NumberOperator OP_NPR = new NumberOperator(OperatorAssociativity.RIGHT, OperatorType.BINARY_INFIX, 0) {
         @Override
-        protected boolean matchesParams(NumberInterface[] params) {
+        public boolean matchesParams(NumberInterface[] params) {
             return params.length == 2 && params[0].fractionalPart().signum() == 0
                     && params[1].fractionalPart().signum() == 0;
         }
 
         @Override
-        protected NumberInterface applyInternal(NumberInterface[] params) {
+        public NumberInterface applyInternal(NumberInterface[] params) {
-            if(params[0].compareTo(params[1]) < 0 ||
+            if (params[0].compareTo(params[1]) < 0 ||
                     params[0].signum() < 0 ||
                     (params[0].signum() == 0 && params[1].signum() != 0)) return fromInt(params[0].getClass(), 0);
             NumberInterface total = fromInt(params[0].getClass(), 1);
             NumberInterface multiplyBy = params[0];
             NumberInterface remainingMultiplications = params[1];
             NumberInterface halfway = params[0].divide(fromInt(params[0].getClass(), 2));
-            if(remainingMultiplications.compareTo(halfway) > 0){
+            if (remainingMultiplications.compareTo(halfway) > 0) {
                 remainingMultiplications = params[0].subtract(remainingMultiplications);
             }
-            while(remainingMultiplications.signum() > 0){
+            while (remainingMultiplications.signum() > 0) {
                 total = total.multiply(multiplyBy);
                 remainingMultiplications = remainingMultiplications.subtract(fromInt(params[0].getClass(), 1));
                 multiplyBy = multiplyBy.subtract(fromInt(params[0].getClass(), 1));
             }
             return total;
         }
-    });
+    };
     /**
      * The combination operator.
      */
-    public static final Operator OP_NCR = new Operator(OperatorAssociativity.RIGHT, OperatorType.BINARY_INFIX, 0, new Function() {
+    public static final NumberOperator OP_NCR = new NumberOperator(OperatorAssociativity.RIGHT, OperatorType.BINARY_INFIX, 0) {
         @Override
-        protected boolean matchesParams(NumberInterface[] params) {
+        public boolean matchesParams(NumberInterface[] params) {
             return params.length == 2 && params[0].fractionalPart().signum() == 0
                     && params[1].fractionalPart().signum() == 0;
         }
 
         @Override
-        protected NumberInterface applyInternal(NumberInterface[] params) {
+        public NumberInterface applyInternal(NumberInterface[] params) {
-            return OP_NPR.getFunction().apply(params).divide(OP_FACTORIAL.getFunction().apply(params[1]));
+            return OP_NPR.apply(params).divide(OP_FACTORIAL.apply(params[1]));
         }
-    });
+    };
     /**
      * The absolute value function, abs(-3) = 3
      */
-    public static final Function FUNCTION_ABS = new Function() {
+    public static final NumberFunction FUNCTION_ABS = new NumberFunction() {
         @Override
-        protected boolean matchesParams(NumberInterface[] params) {
+        public boolean matchesParams(NumberInterface[] params) {
             return params.length == 1;
         }
 
         @Override
-        protected NumberInterface applyInternal(NumberInterface[] params) {
+        public NumberInterface applyInternal(NumberInterface[] params) {
             return params[0].multiply(fromInt(params[0].getClass(), params[0].signum()));
         }
     };
     /**
      * The natural log function.
      */
-    public static final Function FUNCTION_LN = new Function() {
+    public static final NumberFunction FUNCTION_LN = new NumberFunction() {
         @Override
-        protected boolean matchesParams(NumberInterface[] params) {
+        public boolean matchesParams(NumberInterface[] params) {
             return params.length == 1 && params[0].compareTo(fromInt(params[0].getClass(), 0)) > 0;
         }
 
         @Override
-        protected NumberInterface applyInternal(NumberInterface[] params) {
+        public NumberInterface applyInternal(NumberInterface[] params) {
             NumberInterface param = params[0];
             NumberInterface one = fromInt(param.getClass(), 1);
             int powersOf2 = 0;
@@ -277,101 +325,37 @@ public class StandardPlugin extends Plugin {
             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())));
-        }
-    };
     /**
      * Gets a random number smaller or equal to the given number's integer value.
      */
-    public static final Function FUNCTION_RAND_INT = new Function() {
+    public static final NumberFunction FUNCTION_RAND_INT = new NumberFunction() {
         @Override
-        protected boolean matchesParams(NumberInterface[] params) {
+        public boolean matchesParams(NumberInterface[] params) {
             return params.length == 1;
         }
 
         @Override
-        protected NumberInterface applyInternal(NumberInterface[] params) {
+        public NumberInterface applyInternal(NumberInterface[] params) {
             return fromInt(params[0].getClass(), (int) Math.round(Math.random() * params[0].floor().intValue()));
         }
     };
-    /**
-     * 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 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);
-        }
-    };
     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() {
+    public static final NumberFunction FUNCTION_EXP = new NumberFunction() {
         @Override
-        protected boolean matchesParams(NumberInterface[] params) {
+        public boolean matchesParams(NumberInterface[] params) {
             return params.length == 1;
         }
 
         @Override
-        protected NumberInterface applyInternal(NumberInterface[] params) {
+        public 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));
+                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.
@@ -396,9 +380,9 @@ public class StandardPlugin extends Plugin {
     /**
      * The caret / pow operator, ^
      */
-    public static final Operator OP_CARET = new Operator(OperatorAssociativity.RIGHT, OperatorType.BINARY_INFIX, 2, new Function() {
+    public static final NumberOperator OP_CARET = new NumberOperator(OperatorAssociativity.RIGHT, OperatorType.BINARY_INFIX, 2) {
         @Override
-        protected boolean matchesParams(NumberInterface[] params) {
+        public boolean matchesParams(NumberInterface[] params) {
             NumberInterface zero = fromInt(params[0].getClass(), 0);
             return params.length == 2
                     && !(params[0].compareTo(zero) == 0
@@ -407,33 +391,33 @@ public class StandardPlugin extends Plugin {
         }
 
         @Override
-        protected NumberInterface applyInternal(NumberInterface[] params) {
+        public NumberInterface applyInternal(NumberInterface[] params) {
             NumberInterface zero = fromInt(params[0].getClass(), 0);
             if (params[0].compareTo(zero) == 0)
                 return zero;
             else if (params[1].compareTo(zero) == 0)
                 return fromInt(params[0].getClass(), 1);
             //Detect integer bases:
-            if(params[0].fractionalPart().compareTo(fromInt(params[0].getClass(), 0)) == 0
+            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){
+                    && 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() {
+    public final NumberFunction functionSin = new NumberFunction() {
         @Override
-        protected boolean matchesParams(NumberInterface[] params) {
+        public boolean matchesParams(NumberInterface[] params) {
             return params.length == 1;
         }
 
         @Override
-        protected NumberInterface applyInternal(NumberInterface[] params) {
+        public NumberInterface applyInternal(NumberInterface[] params) {
             NumberInterface pi = piFor(params[0].getClass());
             NumberInterface twoPi = pi.multiply(fromInt(pi.getClass(), 2));
             NumberInterface theta = getSmallAngle(params[0], pi);
@@ -450,14 +434,14 @@ public class StandardPlugin extends Plugin {
     /**
      * The cosine function (the argument is in radians).
      */
-    public final Function functionCos = new Function() {
+    public final NumberFunction functionCos = new NumberFunction() {
         @Override
-        protected boolean matchesParams(NumberInterface[] params) {
+        public boolean matchesParams(NumberInterface[] params) {
             return params.length == 1;
         }
 
         @Override
-        protected NumberInterface applyInternal(NumberInterface[] params) {
+        public NumberInterface applyInternal(NumberInterface[] params) {
             return functionSin.apply(piFor(params[0].getClass()).divide(fromInt(params[0].getClass(), 2))
                     .subtract(params[0]));
         }
@@ -465,60 +449,198 @@ public class StandardPlugin extends Plugin {
     /**
      * The tangent function (the argument is in radians).
      */
-    public final Function functionTan = new Function() {
+    public final NumberFunction functionTan = new NumberFunction() {
         @Override
-        protected boolean matchesParams(NumberInterface[] params) {
+        public boolean matchesParams(NumberInterface[] params) {
             return params.length == 1;
         }
 
         @Override
-        protected NumberInterface applyInternal(NumberInterface[] params) {
+        public 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() {
+    public final NumberFunction functionSec = new NumberFunction() {
         @Override
-        protected boolean matchesParams(NumberInterface[] params) {
+        public boolean matchesParams(NumberInterface[] params) {
             return params.length == 1;
         }
 
         @Override
-        protected NumberInterface applyInternal(NumberInterface[] params) {
+        public NumberInterface applyInternal(NumberInterface[] params) {
             return fromInt(params[0].getClass(), 1).divide(functionCos.apply(params[0]));
         }
     };
     /**
      * The cosecant function (the argument is in radians).
      */
-    public final Function functionCsc = new Function() {
+    public final NumberFunction functionCsc = new NumberFunction() {
         @Override
-        protected boolean matchesParams(NumberInterface[] params) {
+        public boolean matchesParams(NumberInterface[] params) {
             return params.length == 1;
         }
 
         @Override
-        protected NumberInterface applyInternal(NumberInterface[] params) {
+        public NumberInterface applyInternal(NumberInterface[] params) {
             return fromInt(params[0].getClass(), 1).divide(functionSin.apply(params[0]));
         }
     };
     /**
      * The cotangent function (the argument is in radians).
      */
-    public final Function functionCot = new Function() {
+    public final NumberFunction functionCot = new NumberFunction() {
         @Override
-        protected boolean matchesParams(NumberInterface[] params) {
+        public boolean matchesParams(NumberInterface[] params) {
             return params.length == 1;
         }
 
         @Override
-        protected NumberInterface applyInternal(NumberInterface[] params) {
+        public NumberInterface applyInternal(NumberInterface[] params) {
             return functionCos.apply(params[0]).divide(functionSin.apply(params[0]));
         }
     };
 
+    /**
+     * The arcsine function (return type in radians).
+     */
+    public final NumberFunction functionArcsin = new NumberFunction() {
+        @Override
+        public boolean matchesParams(NumberInterface[] params) {
+            return params.length == 1
+                    && FUNCTION_ABS.apply(params[0]).compareTo(fromInt(params[0].getClass(), 1)) <= 0;
+        }
+
+        @Override
+        public NumberInterface applyInternal(NumberInterface[] params) {
+            if (FUNCTION_ABS.apply(params[0]).compareTo(new NaiveNumber(0.8).promoteTo(params[0].getClass())) >= 0) {
+                NumberInterface[] newParams = {FUNCTION_SQRT.apply(fromInt(params[0].getClass(), 1).subtract(params[0].multiply(params[0])))};
+                return piFor(params[0].getClass()).divide(fromInt(params[0].getClass(), 2))
+                        .subtract(applyInternal(newParams)).multiply(fromInt(params[0].getClass(), params[0].signum()));
+            }
+            NumberInterface currentTerm = params[0], sum = currentTerm,
+                    multiplier = currentTerm.multiply(currentTerm), summandBound = sum.getMaxError().multiply(fromInt(sum.getClass(), 1).subtract(multiplier)),
+                    power = currentTerm, coefficient = fromInt(params[0].getClass(), 1);
+            int exponent = 1;
+            while (FUNCTION_ABS.apply(currentTerm).compareTo(summandBound) > 0) {
+                exponent += 2;
+                power = power.multiply(multiplier);
+                coefficient = coefficient.multiply(fromInt(params[0].getClass(), exponent - 2))
+                        .divide(fromInt(params[0].getClass(), exponent - 1));
+                currentTerm = power.multiply(coefficient).divide(fromInt(power.getClass(), exponent));
+                sum = sum.add(currentTerm);
+            }
+            return sum;
+        }
+    };
+
+    /**
+     * The arccosine function.
+     */
+    public final NumberFunction functionArccos = new NumberFunction() {
+        @Override
+        public boolean matchesParams(NumberInterface[] params) {
+            return params.length == 1 && FUNCTION_ABS.apply(params[0]).compareTo(fromInt(params[0].getClass(), 1)) <= 0;
+        }
+
+        @Override
+        public NumberInterface applyInternal(NumberInterface[] params) {
+            return piFor(params[0].getClass()).divide(fromInt(params[0].getClass(), 2))
+                    .subtract(functionArcsin.apply(params));
+        }
+    };
+
+    /**
+     * The arccosecant function.
+     */
+    public final NumberFunction functionArccsc = new NumberFunction() {
+        @Override
+        public boolean matchesParams(NumberInterface[] params) {
+            return params.length == 1 && FUNCTION_ABS.apply(params[0]).compareTo(fromInt(params[0].getClass(), 1)) >= 0;
+        }
+
+        @Override
+        public NumberInterface applyInternal(NumberInterface[] params) {
+            NumberInterface[] reciprocalParamArr = {fromInt(params[0].getClass(), 1).divide(params[0])};
+            return functionArcsin.apply(reciprocalParamArr);
+        }
+    };
+
+    /**
+     * The arcsecant function.
+     */
+    public final NumberFunction functionArcsec = new NumberFunction() {
+        @Override
+        public boolean matchesParams(NumberInterface[] params) {
+            return params.length == 1 && FUNCTION_ABS.apply(params[0]).compareTo(fromInt(params[0].getClass(), 1)) >= 0;
+        }
+
+        @Override
+        public NumberInterface applyInternal(NumberInterface[] params) {
+            NumberInterface[] reciprocalParamArr = {fromInt(params[0].getClass(), 1).divide(params[0])};
+            return functionArccos.apply(reciprocalParamArr);
+        }
+    };
+
+    /**
+     * The arctangent function.
+     */
+    public final NumberFunction functionArctan = new NumberFunction() {
+        @Override
+        public boolean matchesParams(NumberInterface[] params) {
+            return params.length == 1;
+        }
+
+        @Override
+        public NumberInterface applyInternal(NumberInterface[] params) {
+            if (params[0].signum() == -1) {
+                NumberInterface[] negatedParams = {params[0].negate()};
+                return applyInternal(negatedParams).negate();
+            }
+            if (params[0].compareTo(fromInt(params[0].getClass(), 1)) > 0) {
+                NumberInterface[] reciprocalParams = {fromInt(params[0].getClass(), 1).divide(params[0])};
+                return piFor(params[0].getClass()).divide(fromInt(params[0].getClass(), 2))
+                        .subtract(applyInternal(reciprocalParams));
+            }
+            if (params[0].compareTo(fromInt(params[0].getClass(), 1)) == 0) {
+                return piFor(params[0].getClass()).divide(fromInt(params[0].getClass(), 4));
+            }
+            if (params[0].compareTo(new NaiveNumber(0.9).promoteTo(params[0].getClass())) >= 0) {
+                NumberInterface[] newParams = {params[0].multiply(fromInt(params[0].getClass(), 2))
+                        .divide(fromInt(params[0].getClass(), 1).subtract(params[0].multiply(params[0])))};
+                return applyInternal(newParams).divide(fromInt(params[0].getClass(), 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(currentTerm).compareTo(maxError) > 0) {
+                n += 2;
+                currentPower = currentPower.multiply(multiplier);
+                currentTerm = currentPower.divide(fromInt(currentPower.getClass(), n));
+                sum = sum.add(currentTerm);
+            }
+            return sum;
+        }
+    };
+
+    /**
+     * The arccotangent function. Range: (0, pi).
+     */
+    public final NumberFunction functionArccot = new NumberFunction() {
+        @Override
+        public boolean matchesParams(NumberInterface[] params) {
+            return params.length == 1;
+        }
+
+        @Override
+        public NumberInterface applyInternal(NumberInterface[] params) {
+            return piFor(params[0].getClass()).divide(fromInt(params[0].getClass(), 2))
+                    .subtract(functionArctan.apply(params));
+        }
+    };
+
     public StandardPlugin(PluginManager manager) {
         super(manager);
     }
@@ -599,15 +721,16 @@ public class StandardPlugin extends Plugin {
 
     /**
      * Returns a number of class numType with value n.
+     *
      * @param numType class of number to return.
-     * @param n value of returned number.
+     * @param n       value of returned number.
      * @return numClass instance with value n.
      */
-    private static NumberInterface fromInt(Class<? extends NumberInterface> numType, int n){
+    private static NumberInterface fromInt(Class<? extends NumberInterface> numType, int n) {
-        if(!integerValues.containsKey(numType)){
+        if (!integerValues.containsKey(numType)) {
             integerValues.put(numType, new HashMap<>());
         }
-        if(!integerValues.get(numType).containsKey(n)){
+        if (!integerValues.get(numType).containsKey(n)) {
             integerValues.get(numType).put(n, new NaiveNumber(n).promoteTo(numType));
         }
         return integerValues.get(numType).get(n);
@@ -633,6 +756,7 @@ public class StandardPlugin extends Plugin {
         registerFunction("exp", FUNCTION_EXP);
         registerFunction("ln", FUNCTION_LN);
         registerFunction("sqrt", FUNCTION_SQRT);
+
         registerFunction("sin", functionSin);
         registerFunction("cos", functionCos);
         registerFunction("tan", functionTan);
@@ -640,6 +764,13 @@ public class StandardPlugin extends Plugin {
         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 " +

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

@@ -0,0 +1,76 @@
+package org.nwapw.abacus.tree;
+
+import org.nwapw.abacus.Abacus;
+import org.nwapw.abacus.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 abacus.numberFromString(((NumberNode) node).getNumber());
+        } else if(node instanceof VariableNode) {
+            return abacus.numberFromString("0");
+        } else if (node instanceof NumberBinaryNode) {
+            NumberInterface left = (NumberInterface) children[0];
+            NumberInterface right = (NumberInterface) children[1];
+            NumberOperator operator = abacus.getPluginManager().operatorFor(((BinaryNode) node).getOperation());
+            return operator.apply(left, right);
+        } else if (node instanceof NumberUnaryNode) {
+            NumberInterface child = (NumberInterface) children[0];
+            NumberOperator operator = abacus.getPluginManager().operatorFor(((UnaryNode) node).getOperation());
+            return operator.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];
+            }
+            NumberFunction function = abacus.getPluginManager().functionFor(((FunctionNode) node).getCallTo());
+            if (function == null) return null;
+            return function.apply(convertedChildren);
+        } else if (node instanceof TreeValueFunctionNode){
+            CallNode callNode = (CallNode) node;
+            TreeNode[] realChildren = new TreeNode[callNode.getChildren().size()];
+            for(int i = 0; i < realChildren.length; i++){
+                realChildren[i] = callNode.getChildren().get(i);
+            }
+            TreeValueFunction function =
+                    abacus.getPluginManager().treeValueFunctionFor(callNode.getCallTo());
+            if(function == null) return null;
+            return function.applyWithReducer(this, realChildren);
+        } else if (node instanceof TreeValueBinaryNode) {
+            BinaryNode binaryNode = (BinaryNode) node;
+            TreeValueOperator operator = abacus.getPluginManager()
+                    .treeValueOperatorFor(binaryNode.getOperation());
+            if(operator == null) return null;
+            return operator.applyWithReducer(this, binaryNode.getLeft(), binaryNode.getRight());
+        } else if(node instanceof TreeValueUnaryNode) {
+            UnaryNode unaryNode = (UnaryNode) node;
+            TreeValueOperator operator = abacus.getPluginManager()
+                    .treeValueOperatorFor(unaryNode.getOperation());
+            if(operator == null) return null;
+            return operator.applyWithReducer(this, unaryNode.getApplyTo());
+        }
+        return null;
+    }
+
+}

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

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

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

@@ -0,0 +1,12 @@
+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

@@ -0,0 +1,17 @@
+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/Operator.kt

@@ -3,12 +3,11 @@ package org.nwapw.abacus.function
 /**
  * A single operator that can be used by Abacus.
  *
- * This is a data class that holds the information about a single operator, such as a plus or minus.
+ * This is a 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.
  */
-data class Operator(val associativity: OperatorAssociativity, val type: OperatorType,
+open class Operator(val associativity: OperatorAssociativity, val type: OperatorType,
-                    val precedence: Int, val function: Function)
+                    val precedence: Int)

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

@@ -0,0 +1,13 @@
+package org.nwapw.abacus.function
+
+import org.nwapw.abacus.function.applicable.ReducerApplicable
+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 : ReducerApplicable<TreeNode, NumberInterface, NumberInterface>

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

@@ -0,0 +1,18 @@
+package org.nwapw.abacus.function
+
+import org.nwapw.abacus.function.applicable.ReducerApplicable
+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),
+        ReducerApplicable<TreeNode, NumberInterface, NumberInterface>

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

@@ -0,0 +1,40 @@
+package org.nwapw.abacus.function.applicable
+
+/**
+ * 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(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(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(vararg params: T): O? {
+        if (!matchesParams(params)) return null
+        return applyInternal(params)
+    }
+
+}

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

@@ -0,0 +1,43 @@
+package org.nwapw.abacus.function.applicable
+
+import org.nwapw.abacus.tree.Reducer
+
+/**
+ * Applicable that requires a reducer.
+ *
+ * ReducerApplicable slightly more specific Applicable that requires a reducer
+ * to be passed to it along with the parameters.
+ * @param <T> the type of the input arguments.
+ * @param <O> the return type of the application.
+ * @param <R> the required type of the reducer.
+ */
+interface ReducerApplicable<in T : Any, out O : Any, in R : Any> {
+
+    /**
+     * Checks if this applicable can be applied to the
+     * given parameters.
+     * @param params the parameters to check.
+     */
+    fun matchesParams(params: Array<out T>): Boolean
+
+    /**
+     * Applies this applicable to the given arguments, and reducer.
+     * @param reducer the reducer to use in the application.
+     * @param params the arguments to apply to.
+     * @return the result of the application.
+     */
+    fun applyWithReducerInternal(reducer: Reducer<R>, params: Array<out T>): O?
+
+    /**
+     * Applies this applicable to the given arguments, and reducer,
+     * if the arguments and reducer are compatible with this applicable.
+     * @param reducer the reducer to use in the application.
+     * @param params the arguments to apply to.
+     * @return the result of the application, or null if the arguments are incompatible.
+     */
+    fun applyWithReducer(reducer: Reducer<R>, vararg params: T): O? {
+        if (!matchesParams(params)) return null
+        return applyWithReducerInternal(reducer, params)
+    }
+
+}

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

@@ -11,13 +11,7 @@ package org.nwapw.abacus.tree
  * @param left the left node.
  * @param right the right node.
  */
-data class BinaryNode(val operation: String, val left: TreeNode? = null, val right: TreeNode?) : TreeNode() {
+abstract 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() ?: "null") + operation + (right?.toString() ?: "null") + ")"

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

@@ -0,0 +1,29 @@
+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.
+ */
+abstract class CallNode(val callTo: String) : TreeNode() {
+
+    /**
+     * The list of children this node has.
+     */
+    val children: MutableList<TreeNode> = mutableListOf()
+
+    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/FunctionNode.kt

@@ -0,0 +1,18 @@
+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) : CallNode(function) {
+
+    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)
+    }
+
+}

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

@@ -0,0 +1,22 @@
+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) ?: return null
+        val right = right?.reduce(reducer) ?: return null
+        return reducer.reduceNode(this, left, right)
+    }
+
+}

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

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

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

@@ -0,0 +1,19 @@
+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 null
+        return reducer.reduceNode(this, child)
+    }
+
+}

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

@@ -6,7 +6,7 @@ package org.nwapw.abacus.tree
  * 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> {
+interface Reducer<out T> {
 
     /**
      * Reduces the given tree node, given its already reduced children.
@@ -14,6 +14,6 @@ interface Reducer <out T> {
      * @param treeNode the tree node to reduce.
      * @param children the list of children, of type T.
      */
-    fun reduceNode(treeNode: TreeNode, vararg children: Any) : T?
+    fun reduceNode(treeNode: TreeNode, vararg children: Any): T?
 
 }

core/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?
 
 }

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

@@ -0,0 +1,21 @@
+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

@@ -0,0 +1,16 @@
+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) : CallNode(name) {
+
+    override fun <T : Any> reduce(reducer: Reducer<T>): T? {
+        return reducer.reduceNode(this)
+    }
+
+}

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

@@ -0,0 +1,19 @@
+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/UnaryNode.kt

@@ -9,12 +9,7 @@ package org.nwapw.abacus.tree
  * @param operation the operation applied to the given node.
  * @param applyTo the node to which the operation will be applied.
  */
-data class UnaryNode(val operation: String, val applyTo: TreeNode? = null) : TreeNode() {
+abstract class UnaryNode(val operation: String, val applyTo: TreeNode? = null) : TreeNode() {
-
-    override fun <T : Any> reduce(reducer: Reducer<T>): T? {
-        val reducedChild = applyTo?.reduce(reducer) ?: return null
-        return reducer.reduceNode(this, reducedChild)
-    }
 
     override fun toString(): String {
         return "(" + (applyTo?.toString() ?: "null") + ")" + operation

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

@@ -0,0 +1,21 @@
+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
+    }
+
+}

core/src/test/java/org/nwapw/abacus/tests/CalculationTests.java

@@ -14,12 +14,12 @@ public class CalculationTests {
     private static Abacus abacus = new Abacus(new Configuration(0, "precise", new String[]{}));
 
     @BeforeClass
-    public static void prepareTests(){
+    public static void prepareTests() {
         abacus.getPluginManager().addInstantiated(new StandardPlugin(abacus.getPluginManager()));
         abacus.getPluginManager().load();
     }
 
-    private void testOutput(String input, String parseOutput, String output){
+    private void testOutput(String input, String parseOutput, String output) {
         TreeNode parsedTree = abacus.parseString(input);
         Assert.assertNotNull(parsedTree);
         Assert.assertEquals(parsedTree.toString(), parseOutput);
@@ -28,7 +28,7 @@ public class CalculationTests {
         Assert.assertTrue(result.toString().startsWith(output));
     }
 
-    private void testEvalError(String input, String parseOutput){
+    private void testEvalError(String input, String parseOutput) {
         TreeNode parsedTree = abacus.parseString(input);
         Assert.assertNotNull(parsedTree);
         Assert.assertEquals(parsedTree.toString(), parseOutput);
@@ -36,56 +36,56 @@ public class CalculationTests {
     }
 
     @Test
-    public void testAddition(){
+    public void testAddition() {
         testOutput("9.5+10", "(9.5+10)", "19.5");
     }
 
     @Test
-    public void testSubtraction(){
+    public void testSubtraction() {
         testOutput("9.5-10", "(9.5-10)", "-0.5");
     }
 
     @Test
-    public void testMultiplication(){
+    public void testMultiplication() {
         testOutput("9.5*10", "(9.5*10)", "95");
     }
 
     @Test
-    public void testDivision(){
+    public void testDivision() {
         testOutput("9.5/2", "(9.5/2)", "4.75");
     }
 
     @Test
-    public void testNegation(){
+    public void testNegation() {
         testOutput("-9.5", "(9.5)`", "-9.5");
     }
 
     @Test
-    public void testFactorial(){
+    public void testFactorial() {
         testOutput("7!", "(7)!", "5040");
     }
 
     @Test
-    public void testAbs(){
+    public void testAbs() {
         testOutput("abs(-1)", "abs((1)`)", "1");
         testOutput("abs(1)", "abs(1)", "1");
     }
 
     @Test
-    public void testLn(){
+    public void testLn() {
         testEvalError("ln(-1)", "ln((1)`)");
         testOutput("ln2", "ln(2)", "0.6931471805599453094172321214581765680755");
     }
 
     @Test
-    public void testSqrt(){
+    public void testSqrt() {
         testOutput("sqrt0", "sqrt(0)", "0");
         testOutput("sqrt4", "sqrt(4)", "2");
         testOutput("sqrt2", "sqrt(2)", "1.4142135623730950488016887242096980785696");
     }
 
     @Test
-    public void testExp(){
+    public void testExp() {
         testOutput("exp0", "exp(0)", "1");
         testOutput("exp1", "exp(1)", "2.718281828459045235360287471352662497757247");
         testOutput("exp300", "exp(300)", "1.9424263952412559365842088360176992193662086");
@@ -93,7 +93,7 @@ public class CalculationTests {
     }
 
     @Test
-    public void testPow(){
+    public void testPow() {
         testOutput("0^2", "(0^2)", "0");
         testOutput("2^0", "(2^0)", "1");
         testOutput("2^1", "(2^1)", "2");
@@ -101,7 +101,7 @@ public class CalculationTests {
         testOutput("2^50", "(2^50)", "112589990684262");
         testOutput("7^(-sqrt2*17)", "(7^((sqrt(2)*17))`)", "4.81354609155297814551845300063563");
         testEvalError("0^0", "(0^0)");
-        testEvalError("(-13)^.9999", "((13)`^0.9999)");
+        testEvalError("(-13)^.9999", "((13)`^.9999)");
     }
 
 }

core/src/test/java/org/nwapw/abacus/tests/TokenizerTests.java

@@ -5,10 +5,7 @@ import org.junit.BeforeClass;
 import org.junit.Test;
 import org.nwapw.abacus.Abacus;
 import org.nwapw.abacus.config.Configuration;
-import org.nwapw.abacus.function.Function;
+import org.nwapw.abacus.function.*;
-import org.nwapw.abacus.function.Operator;
-import org.nwapw.abacus.function.OperatorAssociativity;
-import org.nwapw.abacus.function.OperatorType;
 import org.nwapw.abacus.lexing.pattern.Match;
 import org.nwapw.abacus.number.NumberInterface;
 import org.nwapw.abacus.parsing.LexerTokenizer;
@@ -21,24 +18,46 @@ public class TokenizerTests {
 
     private static Abacus abacus = new Abacus(new Configuration(0, "precise", new String[]{}));
     private static LexerTokenizer lexerTokenizer = new LexerTokenizer();
-    private static Function subtractFunction = new Function() {
+    private static NumberFunction subtractFunction = new NumberFunction() {
         @Override
-        protected boolean matchesParams(NumberInterface[] params) {
+        public boolean matchesParams(NumberInterface[] params) {
             return params.length == 2;
         }
 
         @Override
-        protected NumberInterface applyInternal(NumberInterface[] params) {
+        public NumberInterface applyInternal(NumberInterface[] params) {
             return params[0].subtract(params[1]);
         }
     };
     private static Plugin testPlugin = new Plugin(abacus.getPluginManager()) {
         @Override
         public void onEnable() {
-            registerOperator("+", new Operator(OperatorAssociativity.LEFT, OperatorType.BINARY_INFIX,
+            registerOperator("+", new NumberOperator(OperatorAssociativity.LEFT, OperatorType.BINARY_INFIX,
-                    0, subtractFunction));
+                    0) {
-            registerOperator("-", new Operator(OperatorAssociativity.LEFT, OperatorType.BINARY_INFIX,
+
-                    0, subtractFunction));
+                @Override
+                public boolean matchesParams(NumberInterface[] params) {
+                    return true;
+                }
+
+                @Override
+                public NumberInterface applyInternal(NumberInterface[] params) {
+                    return subtractFunction.apply(params);
+                }
+            });
+            registerOperator("-", new NumberOperator(OperatorAssociativity.LEFT, OperatorType.BINARY_INFIX,
+                    0) {
+
+                @Override
+                public boolean matchesParams(NumberInterface[] params) {
+                    return true;
+                }
+
+                @Override
+                public NumberInterface applyInternal(NumberInterface[] params) {
+                    return subtractFunction.apply(params);
+                }
+            });
             registerFunction("subtract", subtractFunction);
         }
 

docs/404.html

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

docs/Gemfile

@@ -0,0 +1,27 @@
+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

@@ -0,0 +1,58 @@
+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

@@ -0,0 +1,43 @@
+# 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

@@ -0,0 +1,17 @@
+<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

@@ -0,0 +1,10 @@
+<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

@@ -0,0 +1,17 @@
+<!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

@@ -0,0 +1,53 @@
+<!DOCTYPE html>
+<html>
+  {% include head.html %}
+  <style>
+  body {
+    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;
+  }
+  </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"/>
+  </body>
+</html>

docs/_layouts/page.html

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

docs/_pages/about.md

@@ -0,0 +1,27 @@
+---
+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

@@ -0,0 +1,34 @@
+---
+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

@@ -0,0 +1,119 @@
+---
+---
+@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: Helvetica;
+$code-font: "Source Code Pro";
+$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

@@ -0,0 +1,6 @@
+---
+# 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

@@ -0,0 +1,7 @@
+apply plugin: 'application'
+
+dependencies {
+    compile project(':core')
+}
+
+mainClassName = 'org.nwapw.abacus.fx.AbacusApplication'

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

@@ -17,6 +17,10 @@ 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"));
@@ -33,4 +37,5 @@ public class AbacusApplication extends Application {
         super.stop();
         controller.performStop();
     }
+
 }

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

@@ -1,13 +1,10 @@
 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;
 import javafx.fxml.FXML;
-import javafx.scene.Node;
 import javafx.scene.control.*;
 import javafx.scene.control.cell.CheckBoxListCell;
 import javafx.scene.text.Text;
@@ -136,36 +133,12 @@ public class AbacusController implements PluginListener {
      * 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) {
@@ -180,7 +153,7 @@ public class AbacusController implements PluginListener {
                 return resultingString;
             } catch (ComputationInterruptedException exception) {
                 return ERR_STOP;
-            } catch (RuntimeException exception){
+            } catch (RuntimeException exception) {
                 exception.printStackTrace();
                 return ERR_EXCEPTION;
             }
@@ -197,6 +170,18 @@ 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.
      */
@@ -205,6 +190,18 @@ 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 {
+            Configuration abacusConfig = 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
@@ -265,7 +262,7 @@ public class AbacusController implements PluginListener {
 
         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 +289,12 @@ 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;
         }
@@ -312,7 +309,7 @@ public class AbacusController implements PluginListener {
     }
 
     @FXML
-    public void performScan(){
+    public void performScan() {
         PluginManager abacusPluginManager = abacus.getPluginManager();
         abacusPluginManager.removeAll();
         abacusPluginManager.addInstantiated(new StandardPlugin(abacus.getPluginManager()));
@@ -339,7 +336,7 @@ 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)
             configuration.setComputationDelay(Double.parseDouble(computationLimitField.getText()));
         configuration.saveTo(CONFIG_FILE);
         changesMade = false;
@@ -363,6 +360,8 @@ public class AbacusController implements PluginListener {
         PluginManager pluginManager = abacus.getPluginManager();
         functionList.addAll(manager.getAllFunctions().stream().map(name -> pluginManager.documentationFor(name, DocumentationType.FUNCTION))
                 .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));
     }
 

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

@@ -14,7 +14,7 @@ public class DocumentationCell extends ListCell<Documentation> {
     private Label longDescription;
     private TitledPane titledPane;
 
-    public DocumentationCell(){
+    public DocumentationCell() {
         VBox vbox = new VBox();
         vbox.setSpacing(10);
         titledPane = new TitledPane();
@@ -41,7 +41,7 @@ public class DocumentationCell extends ListCell<Documentation> {
     @Override
     protected void updateItem(Documentation item, boolean empty) {
         super.updateItem(item, empty);
-        if(empty){
+        if (empty) {
             codeNameLabel.setText("");
             nameLabel.setText("");
             description.setText("");

fx/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.

fx/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.

settings.gradle

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

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

@@ -1,7 +0,0 @@
-package org.nwapw.abacus.function;
-
-public enum DocumentationType {
-
-    FUNCTION
-
-}

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

@@ -1,39 +0,0 @@
-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/tree/NumberReducer.java

@@ -1,54 +0,0 @@
-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/window/HistoryTableModel.java

@@ -1,106 +0,0 @@
-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

@@ -1,255 +0,0 @@
-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/tree/FunctionNode.kt

@@ -1,52 +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.
- */
-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)
-    }
-
-}