Fix toString errors failing unit tests.

# Conflicts:
#	src/main/java/org/nwapw/abacus/plugin/StandardPlugin.java

build.gradle

@@ -1,3 +1,8 @@
+plugins {
+    id 'java'
+    id 'application'
+    id 'org.jetbrains.kotlin.jvm' version '1.1.3'
+}
 apply plugin: 'java'
 apply plugin: 'application'
 
@@ -7,6 +12,7 @@ repositories {
 
 dependencies {
     compile 'com.moandjiezana.toml:toml4j:0.7.1'
+    compile "org.jetbrains.kotlin:kotlin-stdlib-jre8"
     testCompile 'junit:junit:4.12'
 }
 

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

@@ -30,6 +30,10 @@ public class Configuration {
      */
     private static final TomlWriter TOML_WRITER = new TomlWriter();
 
+    /**
+     * The computation delay for which the thread can run without interruption.
+     */
+    private double computationDelay = 0;
     /**
      * The implementation of the number that should be used.
      */
@@ -51,10 +55,12 @@ public class Configuration {
     /**
      * Creates a new configuration with the given values.
      *
+     * @param computationDelay     the delay before the computation gets killed.
      * @param numberImplementation the number implementation, like "naive" or "precise"
      * @param disabledPlugins      the list of disabled plugins.
      */
-    public Configuration(String numberImplementation, String[] disabledPlugins) {
+    public Configuration(double computationDelay, String numberImplementation, String[] disabledPlugins) {
+        this.computationDelay = computationDelay;
         this.numberImplementation = numberImplementation;
         this.disabledPlugins.addAll(Arrays.asList(disabledPlugins));
     }
@@ -75,6 +81,7 @@ public class Configuration {
      * @param otherConfiguration the configuration to copy from.
      */
     public void copyFrom(Configuration otherConfiguration) {
+        this.computationDelay = otherConfiguration.computationDelay;
         this.numberImplementation = otherConfiguration.numberImplementation;
         this.disabledPlugins.addAll(otherConfiguration.disabledPlugins);
     }
@@ -130,4 +137,23 @@ public class Configuration {
         return disabledPlugins;
     }
 
+
+    /**
+     * Gets the computation delay specified in the configuration.
+     *
+     * @return the computaton delay.
+     */
+    public double getComputationDelay() {
+        return computationDelay;
+    }
+
+    /**
+     * Sets the computation delay.
+     *
+     * @param computationDelay the new computation delay.
+     */
+    public void setComputationDelay(double computationDelay) {
+        this.computationDelay = computationDelay;
+    }
+
 }

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

@@ -1,76 +0,0 @@
-package org.nwapw.abacus.function;
-
-/**
- * A class that represents a single infix operator.
- */
-public class Operator {
-
-    /**
-     * The associativity of the operator.
-     */
-    private OperatorAssociativity associativity;
-    /**
-     * The type of this operator.
-     */
-    private OperatorType type;
-    /**
-     * The precedence of the operator.
-     */
-    private int precedence;
-    /**
-     * The function that is called by this operator.
-     */
-    private Function function;
-
-    /**
-     * Creates a new operator with the given parameters.
-     *
-     * @param associativity the associativity of the operator.
-     * @param operatorType  the type of this operator, like binary infix or unary postfix.
-     * @param precedence    the precedence of the operator.
-     * @param function      the function that the operator calls.
-     */
-    public Operator(OperatorAssociativity associativity, OperatorType operatorType, int precedence, Function function) {
-        this.associativity = associativity;
-        this.type = operatorType;
-        this.precedence = precedence;
-        this.function = function;
-    }
-
-    /**
-     * Gets the operator's associativity.
-     *
-     * @return the associativity.
-     */
-    public OperatorAssociativity getAssociativity() {
-        return associativity;
-    }
-
-    /**
-     * Gets the operator's type.
-     *
-     * @return the type.
-     */
-    public OperatorType getType() {
-        return type;
-    }
-
-    /**
-     * Gets the operator's precedence.
-     *
-     * @return the precedence.
-     */
-    public int getPrecedence() {
-        return precedence;
-    }
-
-    /**
-     * Gets the operator's function.
-     *
-     * @return the function.
-     */
-    public Function getFunction() {
-        return function;
-    }
-
-}

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

@@ -12,13 +12,25 @@ import javafx.stage.Stage;
  */
 public class AbacusApplication extends Application {
 
+    /**
+     * The controller currently managing the application.
+     */
+    private AbacusController controller;
+
     @Override
     public void start(Stage primaryStage) throws Exception {
-        Parent parent = FXMLLoader.load(getClass().getResource("/abacus.fxml"));
+        FXMLLoader loader = new FXMLLoader(getClass().getResource("/abacus.fxml"));
+        Parent parent = loader.load();
+        controller = loader.getController();
         Scene mainScene = new Scene(parent, 320, 480);
         primaryStage.setScene(mainScene);
         primaryStage.setTitle("Abacus");
         primaryStage.show();
     }
 
+    @Override
+    public void stop() throws Exception {
+        super.stop();
+        controller.performStop();
+    }
 }

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

@@ -1,8 +1,11 @@
 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.control.*;
 import javafx.scene.control.cell.CheckBoxListCell;
@@ -70,6 +73,8 @@ public class AbacusController implements PluginListener {
     @FXML
     private Tab settingsTab;
     @FXML
+    private Tab functionListTab;
+    @FXML
     private TableView<HistoryModel> historyTable;
     @FXML
     private TableColumn<HistoryModel, String> inputColumn;
@@ -89,6 +94,12 @@ public class AbacusController implements PluginListener {
     private ComboBox<String> numberImplementationBox;
     @FXML
     private ListView<ToggleablePlugin> enabledPluginView;
+    @FXML
+    private TextField computationLimitField;
+    @FXML
+    private ListView<String> functionListView;
+    @FXML
+    private TextField functionListSearchField;
 
     /**
      * The list of history entries, created by the users.
@@ -106,6 +117,14 @@ public class AbacusController implements PluginListener {
      * and, when reloaded, get added to the plugin manager's black list.
      */
     private ObservableList<ToggleablePlugin> enabledPlugins;
+    /**
+     * The list of functions that are registered in the calculator.
+     */
+    private ObservableList<String> functionList;
+    /**
+     * The filtered list displayed to the user.
+     */
+    private FilteredList<String> functionFilter;
 
     /**
      * The abacus instance used for changing the plugin configuration.
@@ -124,6 +143,17 @@ public class AbacusController implements PluginListener {
      * 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.
      */
@@ -161,6 +191,10 @@ public class AbacusController implements PluginListener {
             });
         }
     };
+    /**
+     * The thread that is waiting to pause the calculation.
+     */
+    private Thread computationLimitThread;
     /**
      * The thread in which the computation runs.
      */
@@ -194,6 +228,11 @@ public class AbacusController implements PluginListener {
                     }
                 });
 
+        functionList = FXCollections.observableArrayList();
+        functionFilter = new FilteredList<>(functionList, (s) -> true);
+        functionListView.setItems(functionFilter);
+        functionListSearchField.textProperty().addListener((observable, oldValue, newValue) ->
+                functionFilter.setPredicate((newValue.length() == 0) ? ((s) -> true) : ((s) -> s.contains(newValue))));
         historyData = FXCollections.observableArrayList();
         historyTable.setItems(historyData);
         numberImplementationOptions = FXCollections.observableArrayList();
@@ -224,6 +263,15 @@ public class AbacusController implements PluginListener {
         }
         abacusPluginManager.reload();
 
+        computationLimitField.setText(Double.toString(abacus.getConfiguration().getComputationDelay()));
+        computationLimitField.textProperty().addListener((observable, oldValue, newValue) -> {
+            if(!newValue.matches("(\\d+(\\.\\d*)?)?")) {
+                computationLimitField.setText(oldValue);
+            } else {
+                changesMade = true;
+            }
+        });
+
         changesMade = false;
         reloadAlertShown = false;
 
@@ -234,21 +282,29 @@ public class AbacusController implements PluginListener {
     }
 
     @FXML
-    private void performCalculation() {
+    public void performCalculation() {
         inputButton.setDisable(true);
         stopButton.setDisable(false);
         calculationThread = new Thread(CALCULATION_RUNNABLE);
         calculationThread.start();
+        computationLimitThread = new Thread(TIMER_RUNNABLE);
+        computationLimitThread.start();
     }
 
     @FXML
-    private void performStop(){
-        if(calculationThread != null)
+    public void performStop(){
+        if(calculationThread != null) {
             calculationThread.interrupt();
+            calculationThread = null;
+        }
+        if(computationLimitThread != null){
+            computationLimitThread.interrupt();
+            computationLimitThread = null;
+        }
     }
 
     @FXML
-    private void performSaveAndReload() {
+    public void performSaveAndReload() {
         performSave();
         performReload();
         changesMade = false;
@@ -256,13 +312,13 @@ public class AbacusController implements PluginListener {
     }
 
     @FXML
-    private void performReload() {
+    public void performReload() {
         alertIfApplyNeeded(true);
         abacus.getPluginManager().reload();
     }
 
     @FXML
-    private void performSave() {
+    public void performSave() {
         Configuration configuration = abacus.getConfiguration();
         configuration.setNumberImplementation(numberImplementationBox.getSelectionModel().getSelectedItem());
         Set<String> disabledPlugins = configuration.getDisabledPlugins();
@@ -270,6 +326,8 @@ 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)
+            configuration.setComputationDelay(Double.parseDouble(computationLimitField.getText()));
         configuration.saveTo(CONFIG_FILE);
         changesMade = false;
         reloadAlertShown = false;
@@ -289,11 +347,15 @@ public class AbacusController implements PluginListener {
             plugin.enabledProperty().addListener(e -> changesMade = true);
             enabledPlugins.add(plugin);
         }
+        functionList.addAll(manager.getAllFunctions());
+        functionList.sort(String::compareTo);
     }
 
     @Override
     public void onUnload(PluginManager manager) {
+        functionList.clear();
         enabledPlugins.clear();
         numberImplementationOptions.clear();
     }
+
 }

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

@@ -173,7 +173,7 @@ public abstract class NumberInterface {
     /**
      * Returns the least integer greater than or equal to the number.
      *
-     * @return the least integer >= the number, if int can hold the value.
+     * @return the least integer greater or equal to the number, if int can hold the value.
      */
     protected abstract NumberInterface ceilingInternal();
 
@@ -182,7 +182,7 @@ public abstract class NumberInterface {
      * Also, checks if the thread has been interrupted, and if so, throws
      * an exception.
      *
-     * @return the least integer bigger or equal to the number, if int can hold the value.
+     * @return the least integer bigger or equal to the number.
      */
     public final NumberInterface ceiling(){
         checkInterrupted();
@@ -192,7 +192,7 @@ public abstract class NumberInterface {
     /**
      * Return the greatest integer less than or equal to the number.
      *
-     * @return the greatest integer smaller or equal the number, if int can hold the value.
+     * @return the greatest integer smaller or equal the number.
      */
     protected abstract NumberInterface floorInternal();
 
@@ -201,7 +201,7 @@ public abstract class NumberInterface {
      * Also, checks if the thread has been interrupted, and if so, throws
      * an exception.
      *
-     * @return the greatest int >= the number, if int can hold the value.
+     * @return the greatest int smaller than or equal to the number.
      */
     public final NumberInterface floor(){
         checkInterrupted();
@@ -216,7 +216,7 @@ public abstract class NumberInterface {
     protected abstract NumberInterface fractionalPartInternal();
 
     /**
-     * Returns the fractional part of the number.
+     * 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.

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

@@ -113,19 +113,18 @@ public class PreciseNumber extends NumberInterface {
         String str = value.toPlainString();
         int decimalIndex = str.indexOf('.');
         if (decimalIndex != -1) {
-            return new PreciseNumber(str.substring(0, decimalIndex));
+            NumberInterface floor = new PreciseNumber(str.substring(0, decimalIndex));
+            if(signum() == -1){
+                floor = floor.subtract(ONE);
+            }
+            return floor;
         }
         return this;
     }
 
     @Override
     public NumberInterface fractionalPartInternal() {
-        String str = value.toPlainString();
-        int decimalIndex = str.indexOf('.');
-        if (decimalIndex != -1) {
-            return new PreciseNumber(str.substring(decimalIndex + 1));
-        }
-        return ZERO;
+        return this.subtractInternal(floorInternal());
     }
 
     @Override

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

@@ -209,6 +209,9 @@ public class PluginManager {
             if (disabledPlugins.contains(plugin.getClass().getName())) continue;
             plugin.disable();
         }
+        registeredFunctions.clear();
+        registeredOperators.clear();
+        registeredNumberImplementations.clear();
         cachedInterfaceImplementations.clear();
         cachedPi.clear();
         listeners.forEach(e -> e.onUnload(this));

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

@@ -18,6 +18,11 @@ 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, +
      */
@@ -112,7 +117,7 @@ public class StandardPlugin extends Plugin {
         @Override
         protected NumberInterface applyInternal(NumberInterface[] params) {
             if (params[0].signum() == 0) {
-                return (new NaiveNumber(1)).promoteTo(params[0].getClass());
+                return fromInt(params[0].getClass(), 1);
             }
             NumberInterface factorial = params[0];
             NumberInterface multiplier = params[0];
@@ -157,14 +162,14 @@ public class StandardPlugin extends Plugin {
             int powersOf2 = 0;
             while (FUNCTION_ABS.apply(param.subtract(NaiveNumber.ONE.promoteTo(param.getClass()))).compareTo(new NaiveNumber(0.1).promoteTo(param.getClass())) >= 0) {
                 if (param.subtract(NaiveNumber.ONE.promoteTo(param.getClass())).signum() == 1) {
-                    param = param.divide(new NaiveNumber(2).promoteTo(param.getClass()));
+                    param = param.divide(fromInt(param.getClass(), 2));
                     powersOf2++;
                     if (param.subtract(NaiveNumber.ONE.promoteTo(param.getClass())).signum() != 1) {
                         break;
                         //No infinite loop for you.
                     }
                 } else {
-                    param = param.multiply(new NaiveNumber(2).promoteTo(param.getClass()));
+                    param = param.multiply(fromInt(param.getClass(), 2));
                     powersOf2--;
                     if (param.subtract(NaiveNumber.ONE.promoteTo(param.getClass())).signum() != -1) {
                         break;
@@ -203,17 +208,17 @@ public class StandardPlugin extends Plugin {
          */
         private NumberInterface getLog2(NumberInterface number) {
             NumberInterface maxError = getMaxError(number);
-            //NumberInterface errorBound = (new NaiveNumber(1)).promoteTo(number.getClass());
+            //NumberInterface errorBound = fromInt(number.getClass(), 1);
             //We'll use the series \sigma_{n >= 1) ((1/3^n + 1/4^n) * 1/n)
             //In the following, a=1/3^n, b=1/4^n, c = 1/n.
             //a is also an error bound.
-            NumberInterface a = (new NaiveNumber(1)).promoteTo(number.getClass()), b = a, c = a;
+            NumberInterface a = fromInt(number.getClass(), 1), b = a, c = a;
             NumberInterface sum = NaiveNumber.ZERO.promoteTo(number.getClass());
             int n = 0;
             while (a.compareTo(maxError) >= 1) {
                 n++;
-                a = a.divide((new NaiveNumber(3)).promoteTo(number.getClass()));
-                b = b.divide((new NaiveNumber(4)).promoteTo(number.getClass()));
+                a = a.divide(fromInt(number.getClass(), 3));
+                b = b.divide(fromInt(number.getClass(), 4));
                 c = NaiveNumber.ONE.promoteTo(number.getClass()).divide((new NaiveNumber(n)).promoteTo(number.getClass()));
                 sum = sum.add(a.add(b).multiply(c));
             }
@@ -311,7 +316,7 @@ public class StandardPlugin extends Plugin {
                 //right and left refer to lhs and rhs in the above inequality.
                 NumberInterface sum = NaiveNumber.ONE.promoteTo(params[0].getClass());
                 NumberInterface nextNumerator = params[0];
-                NumberInterface left = params[0].multiply((new NaiveNumber(3)).promoteTo(params[0].getClass()).intPow(params[0].ceiling().intValue())), right = maxError;
+                NumberInterface left = params[0].multiply(fromInt(params[0].getClass(), 3).intPow(params[0].ceiling().intValue())), right = maxError;
                 do {
                     sum = sum.add(nextNumerator.divide(factorial(params[0].getClass(), n + 1)));
                     n++;
@@ -335,7 +340,8 @@ public class StandardPlugin extends Plugin {
         protected boolean matchesParams(NumberInterface[] params) {
             return params.length == 2
                     && !(params[0].compareTo(NaiveNumber.ZERO.promoteTo(params[0].getClass())) == 0
-                    && params[1].compareTo(NaiveNumber.ZERO.promoteTo(params[1].getClass())) == 0);
+                    && params[1].compareTo(NaiveNumber.ZERO.promoteTo(params[1].getClass())) == 0)
+                    && !(params[0].signum() == -1 && params[1].fractionalPart().compareTo(NaiveNumber.ZERO.promoteTo(params[1].getClass())) != 0);
         }
 
         @Override
@@ -344,6 +350,13 @@ public class StandardPlugin extends Plugin {
                 return NaiveNumber.ZERO.promoteTo(params[0].getClass());
             else if (params[1].compareTo(NaiveNumber.ZERO.promoteTo(params[0].getClass())) == 0)
                 return NaiveNumber.ONE.promoteTo(params[1].getClass());
+            //Detect integer bases:
+            if(params[0].fractionalPart().compareTo(fromInt(params[0].getClass(), 0)) == 0
+                    && FUNCTION_ABS.apply(params[0]).compareTo(fromInt(params[0].getClass(), Integer.MAX_VALUE)) < 0
+                    && FUNCTION_ABS.apply(params[1]).compareTo(fromInt(params[1].getClass(), 1)) >= 0){
+                NumberInterface[] newParams = {params[0], params[1].fractionalPart()};
+                return params[0].intPow(params[1].floor().intValue()).multiply(applyInternal(newParams));
+            }
             return FUNCTION_EXP.apply(FUNCTION_LN.apply(FUNCTION_ABS.apply(params[0])).multiply(params[1]));
         }
     });
@@ -359,12 +372,12 @@ public class StandardPlugin extends Plugin {
         @Override
         protected NumberInterface applyInternal(NumberInterface[] params) {
             NumberInterface pi = piFor(params[0].getClass());
-            NumberInterface twoPi = pi.multiply(new NaiveNumber(2).promoteTo(pi.getClass()));
+            NumberInterface twoPi = pi.multiply(fromInt(pi.getClass(), 2));
             NumberInterface theta = getSmallAngle(params[0], pi);
             //System.out.println(theta);
             if (theta.compareTo(pi.multiply(new NaiveNumber(1.5).promoteTo(twoPi.getClass()))) >= 0) {
                 theta = theta.subtract(twoPi);
-            } else if (theta.compareTo(pi.divide(new NaiveNumber(2).promoteTo(pi.getClass()))) > 0) {
+            } else if (theta.compareTo(pi.divide(fromInt(pi.getClass(), 2))) > 0) {
                 theta = pi.subtract(theta);
             }
             //System.out.println(theta);
@@ -382,7 +395,7 @@ public class StandardPlugin extends Plugin {
 
         @Override
         protected NumberInterface applyInternal(NumberInterface[] params) {
-            return functionSin.apply(piFor(params[0].getClass()).divide(new NaiveNumber(2).promoteTo(params[0].getClass()))
+            return functionSin.apply(piFor(params[0].getClass()).divide(fromInt(params[0].getClass(), 2))
                     .subtract(params[0]));
         }
     };
@@ -470,7 +483,7 @@ public class StandardPlugin extends Plugin {
      * @return the maximum error.
      */
     private static NumberInterface getMaxError(NumberInterface number) {
-        return (new NaiveNumber(10)).promoteTo(number.getClass()).intPow(-number.getMaxPrecision());
+        return fromInt(number.getClass(), 10).intPow(-number.getMaxPrecision());
     }
 
     /**
@@ -531,6 +544,22 @@ public class StandardPlugin extends Plugin {
         return theta;
     }
 
+    /**
+     * Returns a number of class numType with value n.
+     * @param numType class of number to return.
+     * @param n value of returned number.
+     * @return numClass instance with value n.
+     */
+    private static NumberInterface fromInt(Class<? extends NumberInterface> numType, int n){
+        if(!integerValues.containsKey(numType)){
+            integerValues.put(numType, new HashMap<>());
+        }
+        if(!integerValues.get(numType).containsKey(n)){
+            integerValues.get(numType).put(n, new NaiveNumber(n).promoteTo(numType));
+        }
+        return integerValues.get(numType).get(n);
+    }
+
     @Override
     public void onEnable() {
         registerNumberImplementation("naive", IMPLEMENTATION_NAIVE);

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

@@ -1,108 +0,0 @@
-package org.nwapw.abacus.tree;
-
-/**
- * A tree node that represents an operation being applied to two operands.
- */
-public class BinaryNode extends TreeNode {
-
-    /**
-     * The operation being applied.
-     */
-    private String operation;
-    /**
-     * The left node of the operation.
-     */
-    private TreeNode left;
-    /**
-     * The right node of the operation.
-     */
-    private TreeNode right;
-
-    private BinaryNode() {
-    }
-
-    /**
-     * Creates a new operation node with the given operation
-     * and no child nodes.
-     *
-     * @param operation the operation.
-     */
-    public BinaryNode(String operation) {
-        this(operation, null, null);
-    }
-
-    /**
-     * Creates a new operation node with the given operation
-     * and child nodes.
-     *
-     * @param operation the operation.
-     * @param left      the left node of the expression.
-     * @param right     the right node of the expression.
-     */
-    public BinaryNode(String operation, TreeNode left, TreeNode right) {
-        this.operation = operation;
-        this.left = left;
-        this.right = right;
-    }
-
-    /**
-     * Gets the operation in this node.
-     *
-     * @return the operation in this node.
-     */
-    public String getOperation() {
-        return operation;
-    }
-
-    /**
-     * Gets the left sub-expression of this node.
-     *
-     * @return the left node.
-     */
-    public TreeNode getLeft() {
-        return left;
-    }
-
-    /**
-     * Sets the left sub-expression of this node.
-     *
-     * @param left the sub-expression to apply.
-     */
-    public void setLeft(TreeNode left) {
-        this.left = left;
-    }
-
-    /**
-     * Gets the right sub-expression of this node.
-     *
-     * @return the right node.
-     */
-    public TreeNode getRight() {
-        return right;
-    }
-
-    /**
-     * Sets the right sub-expression of this node.
-     *
-     * @param right the sub-expression to apply.
-     */
-    public void setRight(TreeNode right) {
-        this.right = right;
-    }
-
-    @Override
-    public <T> T reduce(Reducer<T> reducer) {
-        T leftReduce = left.reduce(reducer);
-        T rightReduce = right.reduce(reducer);
-        if (leftReduce == null || rightReduce == null) return null;
-        return reducer.reduceNode(this, leftReduce, rightReduce);
-    }
-
-    @Override
-    public String toString() {
-        String leftString = left != null ? left.toString() : "null";
-        String rightString = right != null ? right.toString() : "null";
-
-        return "(" + leftString + operation + rightString + ")";
-    }
-}

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

@@ -1,85 +0,0 @@
-package org.nwapw.abacus.tree;
-
-import java.util.ArrayList;
-import java.util.List;
-
-/**
- * A node that represents a function call.
- */
-public class FunctionNode extends TreeNode {
-
-    /**
-     * The name of the function being called
-     */
-    private String function;
-    /**
-     * The list of arguments to the function.
-     */
-    private List<TreeNode> children;
-
-    /**
-     * Creates a function node with no function.
-     */
-    private FunctionNode() {
-    }
-
-    /**
-     * Creates a new function node with the given function name.
-     *
-     * @param function the function name.
-     */
-    public FunctionNode(String function) {
-        this.function = function;
-        children = new ArrayList<>();
-    }
-
-    /**
-     * Gets the function name for this node.
-     *
-     * @return the function name.
-     */
-    public String getFunction() {
-        return function;
-    }
-
-    /**
-     * Adds a child to the end of this node's child list.
-     *
-     * @param node the child to add.
-     */
-    public void appendChild(TreeNode node) {
-        children.add(node);
-    }
-
-    /**
-     * Adds a new child to the beginning of this node's child list.
-     *
-     * @param node the node to add.
-     */
-    public void prependChild(TreeNode node) {
-        children.add(0, node);
-    }
-
-    @Override
-    public <T> T reduce(Reducer<T> reducer) {
-        Object[] reducedChildren = new Object[children.size()];
-        for (int i = 0; i < reducedChildren.length; i++) {
-            reducedChildren[i] = children.get(i).reduce(reducer);
-            if (reducedChildren[i] == null) return null;
-        }
-        return reducer.reduceNode(this, reducedChildren);
-    }
-
-    @Override
-    public String toString() {
-        StringBuilder buffer = new StringBuilder();
-        buffer.append(function);
-        buffer.append("(");
-        for (int i = 0; i < children.size(); i++) {
-            buffer.append(children.get(i));
-            buffer.append(i == children.size() - 1 ? "" : ", ");
-        }
-        buffer.append(")");
-        return buffer.toString();
-    }
-}

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

@@ -1,49 +0,0 @@
-package org.nwapw.abacus.tree;
-
-import org.nwapw.abacus.number.NumberInterface;
-
-/**
- * A node implementation that represents a single number.
- */
-public class NumberNode extends TreeNode {
-
-    /**
-     * The number that is represented by this number node.
-     */
-    private NumberInterface number;
-
-    /**
-     * Creates a number node with no number.
-     */
-    public NumberNode() {
-        number = null;
-    }
-
-    /**
-     * Creates a new number node with the given double value.
-     *
-     * @param newNumber the number for which to create a number node.
-     */
-    public NumberNode(NumberInterface newNumber) {
-        this.number = newNumber;
-    }
-
-    /**
-     * Gets the number value of this node.
-     *
-     * @return the number value of this node.
-     */
-    public NumberInterface getNumber() {
-        return number;
-    }
-
-    @Override
-    public <T> T reduce(Reducer<T> reducer) {
-        return reducer.reduceNode(this);
-    }
-
-    @Override
-    public String toString() {
-        return number != null ? number.toString() : "null";
-    }
-}

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

@@ -1,17 +0,0 @@
-package org.nwapw.abacus.tree;
-
-/**
- * An abstract class that represents an expression tree node.
- */
-public abstract class TreeNode {
-
-    /**
-     * The function that reduces a tree to a single vale.
-     *
-     * @param reducer the reducer used to reduce the tree.
-     * @param <T>     the type the reducer produces.
-     * @return the result of the reduction, or null on error.
-     */
-    public abstract <T> T reduce(Reducer<T> reducer);
-
-}

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

@@ -1,63 +0,0 @@
-package org.nwapw.abacus.tree;
-
-public class UnaryNode extends TreeNode {
-
-    /**
-     * The operation this node will apply.
-     */
-    private String operation;
-    /**
-     * The tree node to apply the operation to.
-     */
-    private TreeNode applyTo;
-
-    /**
-     * Creates a new node with the given operation and no child.
-     *
-     * @param operation the operation for this node.
-     */
-    public UnaryNode(String operation) {
-        this(operation, null);
-    }
-
-    /**
-     * Creates a new node with the given operation and child.
-     *
-     * @param operation the operation for this node.
-     * @param applyTo   the node to apply the function to.
-     */
-    public UnaryNode(String operation, TreeNode applyTo) {
-        this.operation = operation;
-        this.applyTo = applyTo;
-    }
-
-    @Override
-    public <T> T reduce(Reducer<T> reducer) {
-        Object reducedChild = applyTo.reduce(reducer);
-        if (reducedChild == null) return null;
-        return reducer.reduceNode(this, reducedChild);
-    }
-
-    /**
-     * Gets the operation of this node.
-     *
-     * @return the operation this node performs.
-     */
-    public String getOperation() {
-        return operation;
-    }
-
-    /**
-     * Gets the node to which this node's operation applies.
-     *
-     * @return the tree node to which the operation will be applied.
-     */
-    public TreeNode getApplyTo() {
-        return applyTo;
-    }
-
-    @Override
-    public String toString() {
-        return "(" + (applyTo == null ? "null" : applyTo.toString()) + ")" + operation;
-    }
-}

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

@@ -0,0 +1,14 @@
+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.
+ *
+ * @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,
+                    val precedence: Int, val function: Function)

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

@@ -0,0 +1,26 @@
+package org.nwapw.abacus.tree
+
+/**
+ * A tree node that holds a binary operation.
+ *
+ * This node represents any binary operation, such as binary infix or binary postfix. The only
+ * currently implemented into Abacus is binary infix, but that has more to do with the parser than
+ * this class, which doesn't care about the order that its operation and nodes were found in text.
+ *
+ * @param operation the operation this node performs on its children.
+ * @param left the left node.
+ * @param right the right node.
+ */
+data class BinaryNode(val operation: String, val left: TreeNode? = null, val right: TreeNode?) : TreeNode() {
+
+    override fun <T : Any> reduce(reducer: Reducer<T>): T? {
+        val leftReduce = left?.reduce(reducer) ?: return null
+        val rightReduce = right?.reduce(reducer) ?: return null
+        return reducer.reduceNode(this, leftReduce, rightReduce)
+    }
+
+    override fun toString(): String {
+        return "(" + (left?.toString() ?: "null") + operation + (right?.toString() ?: "null") + ")"
+    }
+
+}

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

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

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

@@ -0,0 +1,23 @@
+package org.nwapw.abacus.tree
+
+import org.nwapw.abacus.number.NumberInterface
+
+/**
+ * A tree node that holds a single number value.
+ *
+ * This is a tree node that holds a single NumberInterface, which represents any number,
+ * and is not defined during compile time.
+ *
+ * @number the number value of this node.
+ */
+data class NumberNode(val number: NumberInterface) : TreeNode() {
+
+    override fun <T : Any> reduce(reducer: Reducer<T>): T? {
+        return reducer.reduceNode(this)
+    }
+
+    override fun toString(): String {
+        return number.toString()
+    }
+
+}

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

@@ -0,0 +1,10 @@
+package org.nwapw.abacus.tree
+
+/**
+ * A tree node.
+ */
+abstract class TreeNode {
+
+    abstract fun <T: Any> reduce(reducer: Reducer<T>) : T?
+
+}

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

@@ -0,0 +1,23 @@
+package org.nwapw.abacus.tree
+
+/**
+ * A tree node that holds a unary operation.
+ *
+ * This node holds a single operator applied to a single parameter, and does not care
+ * whether the operation was found before or after the parameter in the text.
+ *
+ * @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() {
+
+    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
+    }
+
+}

src/main/resources/abacus.fxml

@@ -50,7 +50,9 @@
                     <ListView fx:id="enabledPluginView"
                               GridPane.rowIndex="1" GridPane.columnIndex="0"
                               GridPane.columnSpan="2" maxHeight="100"/>
-                    <FlowPane GridPane.columnIndex="0" GridPane.columnSpan="2" GridPane.rowIndex="2" hgap="10"
+                    <Text GridPane.columnIndex="0" GridPane.rowIndex="2" text="Computation Limit"/>
+                    <TextField fx:id="computationLimitField" GridPane.columnIndex="1" GridPane.rowIndex="2"/>
+                    <FlowPane GridPane.columnIndex="0" GridPane.columnSpan="2" GridPane.rowIndex="3" hgap="10"
                               vgap="10">
                         <Button text="Apply" onAction="#performSave"/>
                         <Button text="Reload Plugins" onAction="#performReload"/>
@@ -58,6 +60,15 @@
                     </FlowPane>
                 </GridPane>
             </Tab>
+            <Tab fx:id="functionListTab" text="Functions" closable="false">
+                <VBox spacing="10">
+                    <padding>
+                        <Insets left="10" right="10" top="10" bottom="10"/>
+                    </padding>
+                    <TextField fx:id="functionListSearchField" maxWidth="Infinity"/>
+                    <ListView maxWidth="Infinity" fx:id="functionListView"/>
+                </VBox>
+            </Tab>
         </TabPane>
     </center>
 

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

@@ -11,7 +11,7 @@ import org.nwapw.abacus.tree.TreeNode;
 
 public class CalculationTests {
 
-    private static Abacus abacus = new Abacus(new Configuration("precise", new String[]{}));
+    private static Abacus abacus = new Abacus(new Configuration(0, "precise", new String[]{}));
 
     @BeforeClass
     public static void prepareTests(){

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

@@ -19,7 +19,7 @@ import java.util.List;
 
 public class TokenizerTests {
 
-    private static Abacus abacus = new Abacus(new Configuration("precise", new String[]{}));
+    private static Abacus abacus = new Abacus(new Configuration(0, "precise", new String[]{}));
     private static LexerTokenizer lexerTokenizer = new LexerTokenizer();
     private static Function subtractFunction = new Function() {
         @Override