Add a filter.

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

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

@@ -46,6 +46,8 @@ public class Abacus {
 
     /**
      * Creates a new instance of the Abacus calculator.
+     *
+     * @param configuration the configuration object for this Abacus instance.
      */
     public Abacus(Configuration configuration) {
         pluginManager = new PluginManager(this);

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

@@ -26,6 +26,7 @@ public class Operator {
      * 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.
      */

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;
@@ -11,6 +14,7 @@ import javafx.util.Callback;
 import javafx.util.StringConverter;
 import org.nwapw.abacus.Abacus;
 import org.nwapw.abacus.config.Configuration;
+import org.nwapw.abacus.number.ComputationInterruptedException;
 import org.nwapw.abacus.number.NumberInterface;
 import org.nwapw.abacus.plugin.ClassFinder;
 import org.nwapw.abacus.plugin.PluginListener;
@@ -58,6 +62,10 @@ public class AbacusController implements PluginListener {
      * Constant string that is displayed if the calculations are stopped before they are done.
      */
     private static final String ERR_STOP = "Stopped";
+    /**
+     * Constant string that is displayed if the calculations are interrupted by an exception.
+     */
+    private static final String ERR_EXCEPTION = "Exception Thrown";
     @FXML
     private TabPane coreTabPane;
     @FXML
@@ -65,6 +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;
@@ -79,9 +89,17 @@ public class AbacusController implements PluginListener {
     @FXML
     private Button inputButton;
     @FXML
+    private Button stopButton;
+    @FXML
     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.
@@ -95,30 +113,23 @@ public class AbacusController implements PluginListener {
     private ObservableList<String> numberImplementationOptions;
 
     /**
-     * <<<<<<< HEAD
      * The list of plugin objects that can be toggled on and off,
      * 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.
      */
     private Abacus abacus;
-    /**
-     * Thread used for calculating.
-     */
-    private Thread calcThread;
-
-    /**
-     * Checks whether the calculator is calculating.
-     */
-    private boolean calculating;
-
-    /**
-     * Seconds delayed for timer;
-     */
-    private double delay = 0;
 
     /**
      * Boolean which represents whether changes were made to the configuration.
@@ -132,6 +143,62 @@ 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.
+     */
+    private final Runnable CALCULATION_RUNNABLE = new Runnable() {
+
+        private String attemptCalculation(){
+            try {
+                TreeNode constructedTree = abacus.parseString(inputField.getText());
+                if (constructedTree == null) {
+                    return ERR_SYNTAX;
+                }
+                NumberInterface evaluatedNumber = abacus.evaluateTree(constructedTree);
+                if (evaluatedNumber == null) {
+                    return ERR_EVAL;
+                }
+                String resultingString = evaluatedNumber.toString();
+                historyData.add(new HistoryModel(inputField.getText(), constructedTree.toString(), resultingString));
+                return resultingString;
+            } catch (ComputationInterruptedException exception) {
+                return ERR_STOP;
+            } catch (RuntimeException exception){
+                exception.printStackTrace();
+                return ERR_EXCEPTION;
+            }
+        }
+
+        @Override
+        public void run() {
+            String calculation = attemptCalculation();
+            Platform.runLater(() -> {
+                outputText.setText(calculation);
+                inputField.setText("");
+                inputButton.setDisable(false);
+                stopButton.setDisable(true);
+            });
+        }
+    };
+    /**
+     * The thread that is waiting to pause the calculation.
+     */
+    private Thread computationLimitThread;
+    /**
+     * The thread in which the computation runs.
+     */
+    private Thread calculationThread;
 
     /**
      * Alerts the user if the changes they made
@@ -161,6 +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();
@@ -191,6 +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;
 
@@ -201,68 +282,29 @@ public class AbacusController implements PluginListener {
     }
 
     @FXML
-    private void performCalculation() {
-        Runnable calculator = new Runnable() {
-            public void run() {
-                if (delay > 0) {
-                    Runnable timer = new Runnable() {
-                        public void run() {
-                            long gap = (long) (delay * 1000);
-                            long startTime = System.currentTimeMillis();
-                            while (System.currentTimeMillis() - startTime <= gap) {
-                            }
-                            stopCalculation();
-                        }
-                    };
-                    Thread maxTime = new Thread(timer);
-                    maxTime.setName("maxTime");
-                    maxTime.start();
-                }
-                calculating = true;
-                Platform.runLater(() -> inputButton.setDisable(true));
-                TreeNode constructedTree = abacus.parseString(inputField.getText());
-                if (constructedTree == null) {
-                    Platform.runLater(() -> outputText.setText(ERR_SYNTAX));
-                    Platform.runLater(() -> inputButton.setDisable(false));
-                    //return;
-                } else {
-                    NumberInterface evaluatedNumber = abacus.evaluateTree(constructedTree);
-                    if (evaluatedNumber == null) {
-                        if (Thread.currentThread().isInterrupted()) {
-                            Platform.runLater(() -> outputText.setText(ERR_STOP));
-                            Platform.runLater(() -> inputButton.setDisable(false));
-                        } else {
-                            Platform.runLater(() -> outputText.setText(ERR_EVAL));
-                            Platform.runLater(() -> inputButton.setDisable(false));
-                            //return;
-                        }
-                    } else {
-                        Platform.runLater(() -> outputText.setText(evaluatedNumber.toString()));
-                        historyData.add(new HistoryModel(inputField.getText(), constructedTree.toString(), evaluatedNumber.toString()));
+    public void performCalculation() {
+        inputButton.setDisable(true);
+        stopButton.setDisable(false);
+        calculationThread = new Thread(CALCULATION_RUNNABLE);
+        calculationThread.start();
+        computationLimitThread = new Thread(TIMER_RUNNABLE);
+        computationLimitThread.start();
+    }
 
-                        Platform.runLater(() -> inputButton.setDisable(false));
-                        Platform.runLater(() -> inputField.setText(""));
-                    }
-                }
-                calculating = false;
-            }
-        };
-        if (!calculating) {
-            calcThread = new Thread(calculator);
-            calcThread.setName("calcThread");
-            calcThread.start();
+    @FXML
+    public void performStop(){
+        if(calculationThread != null) {
+            calculationThread.interrupt();
+            calculationThread = null;
+        }
+        if(computationLimitThread != null){
+            computationLimitThread.interrupt();
+            computationLimitThread = null;
         }
     }
 
     @FXML
-    private void stopCalculation() {
-        calcThread.interrupt();
-        calculating = false;
-        //Platform.runLater(() ->inputButton.setDisable(false));
-    }
-
-    @FXML
-    private void performSaveAndReload() {
+    public void performSaveAndReload() {
         performSave();
         performReload();
         changesMade = false;
@@ -270,13 +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();
@@ -284,6 +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;
@@ -303,11 +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/lexing/pattern/ValueNode.java

@@ -15,7 +15,7 @@ public class ValueNode<T> extends PatternNode<T> {
     /**
      * Creates a new node that matches the given character.
      *
-     * @param value
+     * @param value the character value of the node.
      */
     public ValueNode(char value) {
         this.value = value;

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

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

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

@@ -3,7 +3,7 @@ package org.nwapw.abacus.number;
 /**
  * An implementation of NumberInterface using a double.
  */
-public class NaiveNumber implements NumberInterface {
+public class NaiveNumber extends NumberInterface {
 
     /**
      * The number zero.
@@ -42,32 +42,32 @@ public class NaiveNumber implements NumberInterface {
     }
 
     @Override
-    public NumberInterface multiply(NumberInterface multiplier) {
+    public NumberInterface multiplyInternal(NumberInterface multiplier) {
         return new NaiveNumber(value * ((NaiveNumber) multiplier).value);
     }
 
     @Override
-    public NumberInterface divide(NumberInterface divisor) {
+    public NumberInterface divideInternal(NumberInterface divisor) {
         return new NaiveNumber(value / ((NaiveNumber) divisor).value);
     }
 
     @Override
-    public NumberInterface add(NumberInterface summand) {
+    public NumberInterface addInternal(NumberInterface summand) {
         return new NaiveNumber(value + ((NaiveNumber) summand).value);
     }
 
     @Override
-    public NumberInterface subtract(NumberInterface subtrahend) {
+    public NumberInterface subtractInternal(NumberInterface subtrahend) {
         return new NaiveNumber(value - ((NaiveNumber) subtrahend).value);
     }
 
     @Override
-    public NumberInterface negate() {
+    public NumberInterface negateInternal() {
         return new NaiveNumber(-value);
     }
 
     @Override
-    public NumberInterface intPow(int exponent) {
+    public NumberInterface intPowInternal(int exponent) {
         if (exponent == 0) {
             return NaiveNumber.ONE;
         }
@@ -95,17 +95,17 @@ public class NaiveNumber implements NumberInterface {
     }
 
     @Override
-    public NumberInterface ceiling() {
+    public NumberInterface ceilingInternal() {
         return new NaiveNumber(Math.ceil(value));
     }
 
     @Override
-    public NumberInterface floor() {
+    public NumberInterface floorInternal() {
         return new NaiveNumber(Math.floor(value));
     }
 
     @Override
-    public NumberInterface fractionalPart() {
+    public NumberInterface fractionalPartInternal() {
         return new NaiveNumber(value - Math.floor(value));
     }
 
@@ -115,7 +115,7 @@ public class NaiveNumber implements NumberInterface {
     }
 
     @Override
-    public NumberInterface promoteTo(Class<? extends NumberInterface> toClass) {
+    public NumberInterface promoteToInternal(Class<? extends NumberInterface> toClass) {
         if (toClass == this.getClass()) return this;
         else if (toClass == PreciseNumber.class) {
             return new PreciseNumber(Double.toString(value));

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

@@ -3,14 +3,22 @@ package org.nwapw.abacus.number;
 /**
  * An interface used to represent a number.
  */
-public interface NumberInterface {
+public abstract class NumberInterface {
 
+    /**
+     * Check if the thread was interrupted and
+     * throw an exception to end the computation.
+     */
+    private static void checkInterrupted(){
+        if(Thread.currentThread().isInterrupted())
+            throw new ComputationInterruptedException();
+    }
     /**
      * The maximum precision to which this number operates.
      *
      * @return the precision.
      */
-    int getMaxPrecision();
+    public abstract int getMaxPrecision();
 
     /**
      * Multiplies this number by another, returning
@@ -19,7 +27,21 @@ public interface NumberInterface {
      * @param multiplier the multiplier
      * @return the result of the multiplication.
      */
-    NumberInterface multiply(NumberInterface multiplier);
+    protected abstract NumberInterface multiplyInternal(NumberInterface multiplier);
+
+    /**
+     * Multiplies this number by another, returning
+     * a new number instance. Also, checks if the
+     * thread has been interrupted, and if so, throws
+     * an exception.
+     *
+     * @param multiplier the multiplier
+     * @return the result of the multiplication.
+     */
+    public final NumberInterface multiply(NumberInterface multiplier){
+        checkInterrupted();
+        return multiplyInternal(multiplier);
+    }
 
     /**
      * Divides this number by another, returning
@@ -28,7 +50,21 @@ public interface NumberInterface {
      * @param divisor the divisor
      * @return the result of the division.
      */
-    NumberInterface divide(NumberInterface divisor);
+    protected abstract NumberInterface divideInternal(NumberInterface divisor);
+
+    /**
+     * Divides this number by another, returning
+     * a new number instance. Also, checks if the
+     * thread has been interrupted, and if so, throws
+     * an exception.
+     *
+     * @param divisor the divisor
+     * @return the result of the division.
+     */
+    public final NumberInterface divide(NumberInterface divisor){
+        checkInterrupted();
+        return divideInternal(divisor);
+    }
 
     /**
      * Adds this number to another, returning
@@ -37,7 +73,21 @@ public interface NumberInterface {
      * @param summand the summand
      * @return the result of the summation.
      */
-    NumberInterface add(NumberInterface summand);
+    protected abstract NumberInterface addInternal(NumberInterface summand);
+
+    /**
+     * Adds this number to another, returning
+     * a new number instance. Also, checks if the
+     * thread has been interrupted, and if so, throws
+     * an exception.
+     *
+     * @param summand the summand
+     * @return the result of the summation.
+     */
+    public final NumberInterface add(NumberInterface summand){
+        checkInterrupted();
+        return addInternal(summand);
+    }
 
     /**
      * Subtracts another number from this number,
@@ -46,7 +96,21 @@ public interface NumberInterface {
      * @param subtrahend the subtrahend.
      * @return the result of the subtraction.
      */
-    NumberInterface subtract(NumberInterface subtrahend);
+    protected abstract NumberInterface subtractInternal(NumberInterface subtrahend);
+
+    /**
+     * Subtracts another number from this number,
+     * a new number instance. Also, checks if the
+     * thread has been interrupted, and if so, throws
+     * an exception.
+     *
+     * @param subtrahend the subtrahend.
+     * @return the result of the subtraction.
+     */
+    public final NumberInterface subtract(NumberInterface subtrahend){
+        checkInterrupted();
+        return subtractInternal(subtrahend);
+    }
 
     /**
      * Returns a new instance of this number with
@@ -54,7 +118,21 @@ public interface NumberInterface {
      *
      * @return the new instance.
      */
-    NumberInterface negate();
+    protected abstract NumberInterface negateInternal();
+
+
+    /**
+     * Returns a new instance of this number with
+     * the sign flipped. Also, checks if the
+     * thread has been interrupted, and if so, throws
+     * an exception.
+     *
+     * @return the new instance.
+     */
+    public final NumberInterface negate(){
+        checkInterrupted();
+        return negateInternal();
+    }
 
     /**
      * Raises this number to an integer power.
@@ -62,7 +140,20 @@ public interface NumberInterface {
      * @param exponent the exponent to which to take the number.
      * @return the resulting value.
      */
-    NumberInterface intPow(int exponent);
+    protected abstract NumberInterface intPowInternal(int exponent);
+
+    /**
+     * Raises this number to an integer power. Also, checks if the
+     * thread has been interrupted, and if so, throws
+     * an exception.
+     *
+     * @param exponent the exponent to which to take the number.
+     * @return the resulting value.
+     */
+    public final NumberInterface intPow(int exponent){
+        checkInterrupted();
+        return intPowInternal(exponent);
+    }
 
     /**
      * Compares this number to another.
@@ -70,43 +161,78 @@ public interface NumberInterface {
      * @param number the number to compare to.
      * @return same as Integer.compare();
      */
-    int compareTo(NumberInterface number);
+    public abstract int compareTo(NumberInterface number);
 
     /**
      * Same as Math.signum().
      *
      * @return 1 if this number is positive, -1 if this number is negative, 0 if this number is 0.
      */
-    int signum();
+    public abstract int signum();
 
     /**
      * 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.
      */
-    NumberInterface ceiling();
+    protected abstract NumberInterface ceilingInternal();
+
+    /**
+     * Returns the least integer greater than or equal to the number.
+     * 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.
+     */
+    public final NumberInterface ceiling(){
+        checkInterrupted();
+        return ceilingInternal();
+    }
 
     /**
      * Return the greatest integer less than or equal to the number.
      *
-     * @return the greatest int >= the number, if int can hold the value.
+     * @return the greatest integer smaller or equal the number, if int can hold the value.
      */
-    NumberInterface floor();
+    protected abstract NumberInterface floorInternal();
+
+    /**
+     * Return the greatest integer less than or equal to the number.
+     * Also, checks if the thread has been interrupted, and if so, throws
+     * an exception.
+     *
+     * @return the greatest int smaller or equal to the number, if int can hold the value.
+     */
+    public final NumberInterface floor(){
+        checkInterrupted();
+        return floorInternal();
+    }
 
     /**
      * Returns the fractional part of the number.
      *
      * @return the fractional part of the number.
      */
-    NumberInterface fractionalPart();
+    protected abstract NumberInterface fractionalPartInternal();
+
+    /**
+     * Returns the fractional part of the number.
+     * 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(){
+        checkInterrupted();
+        return fractionalPartInternal();
+    }
 
     /**
      * Returns the integer representation of this number, discarding any fractional part,
      * if int can hold the value.
      *
-     * @return
+     * @return the integer value of this number.
      */
-    int intValue();
+    public abstract int intValue();
 
     /**
      * Promotes this class to another number class.
@@ -114,6 +240,19 @@ public interface NumberInterface {
      * @param toClass the class to promote to.
      * @return the resulting new instance.
      */
-    NumberInterface promoteTo(Class<? extends NumberInterface> toClass);
+    protected abstract NumberInterface promoteToInternal(Class<? extends NumberInterface> toClass);
+
+    /**
+     * Promotes this class to another number class. Also, checks if the
+     * thread has been interrupted, and if so, throws
+     * an exception.
+     *
+     * @param toClass the class to promote to.
+     * @return the resulting new instance.
+     */
+    public final NumberInterface promoteTo(Class<? extends NumberInterface> toClass) {
+        checkInterrupted();
+        return promoteToInternal(toClass);
+    }
 
 }

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

@@ -7,7 +7,7 @@ import java.math.RoundingMode;
  * A number that uses a BigDecimal to store its value,
  * leading to infinite possible precision.
  */
-public class PreciseNumber implements NumberInterface {
+public class PreciseNumber extends NumberInterface {
 
     /**
      * The number one.
@@ -52,27 +52,27 @@ public class PreciseNumber implements NumberInterface {
     }
 
     @Override
-    public NumberInterface multiply(NumberInterface multiplier) {
+    public NumberInterface multiplyInternal(NumberInterface multiplier) {
         return new PreciseNumber(this.value.multiply(((PreciseNumber) multiplier).value));
     }
 
     @Override
-    public NumberInterface divide(NumberInterface divisor) {
+    public NumberInterface divideInternal(NumberInterface divisor) {
         return new PreciseNumber(value.divide(((PreciseNumber) divisor).value, this.getMaxPrecision(), RoundingMode.HALF_UP));
     }
 
     @Override
-    public NumberInterface add(NumberInterface summand) {
+    public NumberInterface addInternal(NumberInterface summand) {
         return new PreciseNumber(value.add(((PreciseNumber) summand).value));
     }
 
     @Override
-    public NumberInterface subtract(NumberInterface subtrahend) {
+    public NumberInterface subtractInternal(NumberInterface subtrahend) {
         return new PreciseNumber(value.subtract(((PreciseNumber) subtrahend).value));
     }
 
     @Override
-    public NumberInterface intPow(int exponent) {
+    public NumberInterface intPowInternal(int exponent) {
         if (exponent == 0) {
             return PreciseNumber.ONE;
         }
@@ -99,7 +99,7 @@ public class PreciseNumber implements NumberInterface {
     }
 
     @Override
-    public NumberInterface ceiling() {
+    public NumberInterface ceilingInternal() {
         String str = value.toPlainString();
         int decimalIndex = str.indexOf('.');
         if (decimalIndex != -1) {
@@ -109,7 +109,7 @@ public class PreciseNumber implements NumberInterface {
     }
 
     @Override
-    public NumberInterface floor() {
+    public NumberInterface floorInternal() {
         String str = value.toPlainString();
         int decimalIndex = str.indexOf('.');
         if (decimalIndex != -1) {
@@ -119,7 +119,7 @@ public class PreciseNumber implements NumberInterface {
     }
 
     @Override
-    public NumberInterface fractionalPart() {
+    public NumberInterface fractionalPartInternal() {
         String str = value.toPlainString();
         int decimalIndex = str.indexOf('.');
         if (decimalIndex != -1) {
@@ -134,12 +134,12 @@ public class PreciseNumber implements NumberInterface {
     }
 
     @Override
-    public NumberInterface negate() {
+    public NumberInterface negateInternal() {
         return new PreciseNumber(value.negate());
     }
 
     @Override
-    public NumberInterface promoteTo(Class<? extends NumberInterface> toClass) {
+    public NumberInterface promoteToInternal(Class<? extends NumberInterface> toClass) {
         if (toClass == this.getClass()) {
             return this;
         }

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

@@ -162,8 +162,10 @@ 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;
         Collections.reverse(tokens);
-        return constructRecursive(tokens);
+        TreeNode constructedTree = constructRecursive(tokens);
+        return tokens.size() == 0 ? constructedTree : null;
     }
 
     @Override

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

@@ -28,7 +28,7 @@ public abstract class NumberImplementation {
      * Creates a new number implementation with the given data.
      *
      * @param implementation the implementation class.
-     * @param priority       the priority, higher -> more likely to be converted into.
+     * @param priority       the priority, higher means more likely to be converted into.
      */
     public NumberImplementation(Class<? extends NumberInterface> implementation, int priority) {
         this.implementation = implementation;

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

@@ -17,18 +17,6 @@ import java.util.Set;
  */
 public abstract class Plugin {
 
-    /**
-     * A hash map of functions mapped to their string names.
-     */
-    private Map<String, Function> functions;
-    /**
-     * A hash map of operators mapped to their string names.
-     */
-    private Map<String, Operator> operators;
-    /**
-     * The map of the number implementations this plugin provides.
-     */
-    private Map<String, NumberImplementation> numberImplementations;
     /**
      * The plugin manager in which to search for functions
      * not inside this package,
@@ -49,69 +37,9 @@ public abstract class Plugin {
      */
     public Plugin(PluginManager manager) {
         this.manager = manager;
-        functions = new HashMap<>();
-        operators = new HashMap<>();
-        numberImplementations = new HashMap<>();
         enabled = false;
     }
 
-    /**
-     * Gets the list of functions provided by this plugin.
-     *
-     * @return the list of registered functions.
-     */
-    public final Set<String> providedFunctions() {
-        return functions.keySet();
-    }
-
-    /**
-     * Gets the list of functions provided by this plugin.
-     *
-     * @return the list of registered functions.
-     */
-    public final Set<String> providedOperators() {
-        return operators.keySet();
-    }
-
-    /**
-     * Gets the list of number implementations provided by this plugin.
-     *
-     * @return the list of registered number implementations.
-     */
-    public final Set<String> providedNumberImplementations() {
-        return numberImplementations.keySet();
-    }
-
-    /**
-     * Gets a function under the given function name.
-     *
-     * @param functionName the name of the function to get
-     * @return the function, or null if this plugin doesn't provide it.
-     */
-    public final Function getFunction(String functionName) {
-        return functions.get(functionName);
-    }
-
-    /**
-     * Gets an operator under the given operator name.
-     *
-     * @param operatorName the name of the operator to get.
-     * @return the operator, or null if this plugin doesn't provide it.
-     */
-    public final Operator getOperator(String operatorName) {
-        return operators.get(operatorName);
-    }
-
-    /**
-     * Gets the number implementation under the given name.
-     *
-     * @param name the name of the number implementation to look up.
-     * @return the number implementation associated with that name, or null if the plugin doesn't provide it.
-     */
-    public final NumberImplementation getNumberImplementation(String name) {
-        return numberImplementations.get(name);
-    }
-
     /**
      * Enables the function, loading the necessary instances
      * of functions.
@@ -129,8 +57,6 @@ public abstract class Plugin {
     public final void disable() {
         if (!enabled) return;
         onDisable();
-        functions.clear();
-        operators.clear();
         enabled = false;
     }
 
@@ -142,7 +68,7 @@ public abstract class Plugin {
      * @param toRegister the function implementation.
      */
     protected final void registerFunction(String name, Function toRegister) {
-        functions.put(name, toRegister);
+        manager.registerFunction(name, toRegister);
     }
 
     /**
@@ -154,7 +80,7 @@ public abstract class Plugin {
      * @param operator the operator to register.
      */
     protected final void registerOperator(String name, Operator operator) {
-        operators.put(name, operator);
+        manager.registerOperator(name, operator);
     }
 
     /**
@@ -165,7 +91,7 @@ public abstract class Plugin {
      * @param implementation the actual implementation class to register.
      */
     protected final void registerNumberImplementation(String name, NumberImplementation implementation) {
-        numberImplementations.put(name, implementation);
+        manager.registerNumberImplementation(name, implementation);
     }
 
     /**
@@ -213,7 +139,7 @@ public abstract class Plugin {
      * @param forClass the class to which to find the pi instance.
      * @return the pi value for the given class.
      */
-    protected final NumberInterface getPi(Class<? extends NumberInterface> forClass) {
+    protected final NumberInterface piFor(Class<? extends NumberInterface> forClass) {
         return manager.piFor(forClass);
     }
 

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

@@ -23,20 +23,17 @@ public class PluginManager {
      */
     private Set<Plugin> plugins;
     /**
-     * List of functions that have been cached,
-     * that is, found in a plugin and returned.
+     * The map of functions registered by the plugins.
      */
-    private Map<String, Function> cachedFunctions;
+    private Map<String, Function> registeredFunctions;
     /**
-     * List of operators that have been cached,
-     * that is, found in a plugin and returned.
+     * The map of operators registered by the plugins
      */
-    private Map<String, Operator> cachedOperators;
+    private Map<String, Operator> registeredOperators;
     /**
-     * The list of number implementations that have
-     * been cached, that is, found in a plugin and returned.
+     * The map of number implementations registered by the plugins.
      */
-    private Map<String, NumberImplementation> cachedNumberImplementations;
+    private Map<String, NumberImplementation> registeredNumberImplementations;
     /**
      * The list of number implementations that have been
      * found by their implementation class.
@@ -46,18 +43,6 @@ public class PluginManager {
      * The pi values for each implementation class that have already been computer.
      */
     private Map<Class<? extends NumberInterface>, NumberInterface> cachedPi;
-    /**
-     * List of all functions loaded by the plugins.
-     */
-    private Set<String> allFunctions;
-    /**
-     * List of all operators loaded by the plugins.
-     */
-    private Set<String> allOperators;
-    /**
-     * List of all the number implementations loaded by the plugins.
-     */
-    private Set<String> allNumberImplementations;
     /**
      * The list of plugin listeners attached to this instance.
      */
@@ -70,84 +55,73 @@ public class PluginManager {
 
     /**
      * Creates a new plugin manager.
+     *
+     * @param abacus the abacus instance.
      */
     public PluginManager(Abacus abacus) {
         this.abacus = abacus;
         loadedPluginClasses = new HashSet<>();
         plugins = new HashSet<>();
-        cachedFunctions = new HashMap<>();
-        cachedOperators = new HashMap<>();
-        cachedNumberImplementations = new HashMap<>();
+        registeredFunctions = new HashMap<>();
+        registeredOperators = new HashMap<>();
+        registeredNumberImplementations = new HashMap<>();
         cachedInterfaceImplementations = new HashMap<>();
         cachedPi = new HashMap<>();
-        allFunctions = new HashSet<>();
-        allOperators = new HashSet<>();
-        allNumberImplementations = new HashSet<>();
         listeners = new HashSet<>();
     }
 
     /**
-     * Searches the plugin list for a certain value, retrieving the Plugin's
-     * list of items of the type using the setFunction and getting the value
-     * of it is available via getFunction. If the value is contained
-     * in the cache, it returns the cached value instead.
-     *
-     * @param plugins     the plugin list to search.
-     * @param cache       the cache to use
-     * @param setFunction the function to retrieve a set of available T's from the plugin
-     * @param getFunction the function to get the T value under the given name
-     * @param name        the name to search for
-     * @param <T>         the type of element being search
-     * @param <K>         the type of key that the cache is indexed by.
-     * @return the retrieved element, or null if it was not found.
+     * Registers a function under the given name.
+     * @param name the name of the function.
+     * @param function the function to register.
      */
-    private static <T, K> T searchCached(Collection<Plugin> plugins, Map<K, T> cache,
-                                         java.util.function.Function<Plugin, Set<K>> setFunction,
-                                         java.util.function.BiFunction<Plugin, K, T> getFunction,
-                                         K name) {
-        if (cache.containsKey(name)) return cache.get(name);
-
-        T loadedValue = null;
-        for (Plugin plugin : plugins) {
-            if (setFunction.apply(plugin).contains(name)) {
-                loadedValue = getFunction.apply(plugin, name);
-                break;
-            }
-        }
-
-        cache.put(name, loadedValue);
-        return loadedValue;
+    public void registerFunction(String name, Function function){
+        registeredFunctions.put(name, function);
     }
 
     /**
-     * Gets a function under the given name.
-     *
-     * @param name the name of the function
-     * @return the function under the given name.
-     */
-    public Function functionFor(String name) {
-        return searchCached(plugins, cachedFunctions, Plugin::providedFunctions, Plugin::getFunction, name);
-    }
-
-    /**
-     * Gets an operator under the given name.
-     *
+     * Registers an operator under the given name.
      * @param name the name of the operator.
-     * @return the operator under the given name.
+     * @param operator the operator to register.
      */
-    public Operator operatorFor(String name) {
-        return searchCached(plugins, cachedOperators, Plugin::providedOperators, Plugin::getOperator, name);
+    public void registerOperator(String name, Operator operator){
+        registeredOperators.put(name, operator);
     }
 
     /**
-     * Gets the number implementation under the given name.
-     *
-     * @param name the name of the implementation.
-     * @return the implementation.
+     * Registers a number implementation under the given name.
+     * @param name the name of the number implementation.
+     * @param implementation the number implementation to register.
      */
-    public NumberImplementation numberImplementationFor(String name) {
-        return searchCached(plugins, cachedNumberImplementations, Plugin::providedNumberImplementations,
-                Plugin::getNumberImplementation, name);
+    public void registerNumberImplementation(String name, NumberImplementation implementation){
+        registeredNumberImplementations.put(name, implementation);
+    }
+
+    /**
+     * 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){
+        return registeredFunctions.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){
+        return registeredOperators.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){
+        return registeredNumberImplementations.get(name);
     }
 
     /**
@@ -159,14 +133,11 @@ public class PluginManager {
     public NumberImplementation interfaceImplementationFor(Class<? extends NumberInterface> name) {
         if (cachedInterfaceImplementations.containsKey(name)) return cachedInterfaceImplementations.get(name);
         NumberImplementation toReturn = null;
-        outside:
-        for (Plugin plugin : plugins) {
-            for (String implementationName : plugin.providedNumberImplementations()) {
-                NumberImplementation implementation = plugin.getNumberImplementation(implementationName);
-                if (implementation.getImplementation().equals(name)) {
-                    toReturn = implementation;
-                    break outside;
-                }
+        for(String key : registeredNumberImplementations.keySet()){
+            NumberImplementation implementation = registeredNumberImplementations.get(key);
+            if(implementation.getImplementation() == name) {
+                toReturn = implementation;
+                break;
             }
         }
         cachedInterfaceImplementations.put(name, toReturn);
@@ -225,12 +196,6 @@ public class PluginManager {
             if (disabledPlugins.contains(plugin.getClass().getName())) continue;
             plugin.enable();
         }
-        for (Plugin plugin : plugins) {
-            if (disabledPlugins.contains(plugin.getClass().getName())) continue;
-            allFunctions.addAll(plugin.providedFunctions());
-            allOperators.addAll(plugin.providedOperators());
-            allNumberImplementations.addAll(plugin.providedNumberImplementations());
-        }
         listeners.forEach(e -> e.onLoad(this));
     }
 
@@ -244,14 +209,11 @@ public class PluginManager {
             if (disabledPlugins.contains(plugin.getClass().getName())) continue;
             plugin.disable();
         }
-        cachedFunctions.clear();
-        cachedOperators.clear();
-        cachedNumberImplementations.clear();
+        registeredFunctions.clear();
+        registeredOperators.clear();
+        registeredNumberImplementations.clear();
         cachedInterfaceImplementations.clear();
         cachedPi.clear();
-        allFunctions.clear();
-        allOperators.clear();
-        allNumberImplementations.clear();
         listeners.forEach(e -> e.onUnload(this));
     }
 
@@ -269,7 +231,7 @@ public class PluginManager {
      * @return the set of all functions that were loaded.
      */
     public Set<String> getAllFunctions() {
-        return allFunctions;
+        return registeredFunctions.keySet();
     }
 
     /**
@@ -278,7 +240,7 @@ public class PluginManager {
      * @return the set of all operators that were loaded.
      */
     public Set<String> getAllOperators() {
-        return allOperators;
+        return registeredOperators.keySet();
     }
 
     /**
@@ -287,7 +249,7 @@ public class PluginManager {
      * @return the set of all implementations that were loaded.
      */
     public Set<String> getAllNumberImplementations() {
-        return allNumberImplementations;
+        return registeredNumberImplementations.keySet();
     }
 
     /**

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, +
      */
@@ -29,13 +34,9 @@ public class StandardPlugin extends Plugin {
 
         @Override
         protected NumberInterface applyInternal(NumberInterface[] params) {
-            if (Thread.currentThread().isInterrupted())
-                return null;
             NumberInterface sum = params[0];
             for (int i = 1; i < params.length; i++) {
                 sum = sum.add(params[i]);
-                if (Thread.currentThread().isInterrupted())
-                    return null;
             }
             return sum;
         }
@@ -51,8 +52,6 @@ public class StandardPlugin extends Plugin {
 
         @Override
         protected NumberInterface applyInternal(NumberInterface[] params) {
-            if (Thread.currentThread().isInterrupted())
-                return null;
             return params[0].subtract(params[1]);
 
         }
@@ -68,8 +67,6 @@ public class StandardPlugin extends Plugin {
 
         @Override
         protected NumberInterface applyInternal(NumberInterface[] params) {
-            if (Thread.currentThread().isInterrupted())
-                return null;
             return params[0].negate();
         }
     });
@@ -84,13 +81,9 @@ public class StandardPlugin extends Plugin {
 
         @Override
         protected NumberInterface applyInternal(NumberInterface[] params) {
-            if (Thread.currentThread().isInterrupted())
-                return null;
             NumberInterface product = params[0];
             for (int i = 1; i < params.length; i++) {
                 product = product.multiply(params[i]);
-                if (Thread.currentThread().isInterrupted())
-                    return null;
             }
             return product;
         }
@@ -106,8 +99,6 @@ public class StandardPlugin extends Plugin {
 
         @Override
         protected NumberInterface applyInternal(NumberInterface[] params) {
-            if (Thread.currentThread().isInterrupted())
-                return null;
             return params[0].divide(params[1]);
         }
     });
@@ -125,19 +116,15 @@ public class StandardPlugin extends Plugin {
 
         @Override
         protected NumberInterface applyInternal(NumberInterface[] params) {
-            if (Thread.currentThread().isInterrupted())
-                return null;
             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];
             //It is necessary to later prevent calls of factorial on anything but non-negative integers.
-            while (!Thread.currentThread().isInterrupted() && (multiplier = multiplier.subtract(NaiveNumber.ONE.promoteTo(multiplier.getClass()))) != null && multiplier.signum() == 1) {
+            while ((multiplier = multiplier.subtract(NaiveNumber.ONE.promoteTo(multiplier.getClass()))).signum() == 1) {
                 factorial = factorial.multiply(multiplier);
             }
-            if (Thread.currentThread().isInterrupted())
-                return null;
             return factorial;
                 /*if(!storedList.containsKey(params[0].getClass())){
                     storedList.put(params[0].getClass(), new ArrayList<NumberInterface>());
@@ -157,8 +144,6 @@ public class StandardPlugin extends Plugin {
 
         @Override
         protected NumberInterface applyInternal(NumberInterface[] params) {
-            if (Thread.currentThread().isInterrupted())
-                return null;
             return params[0].multiply((new NaiveNumber(params[0].signum())).promoteTo(params[0].getClass()));
         }
     };
@@ -173,32 +158,26 @@ public class StandardPlugin extends Plugin {
 
         @Override
         protected NumberInterface applyInternal(NumberInterface[] params) {
-            if (Thread.currentThread().isInterrupted())
-                return null;
             NumberInterface param = params[0];
             int powersOf2 = 0;
-            NumberInterface check;
-            while (!Thread.currentThread().isInterrupted() && (check = FUNCTION_ABS.apply(param.subtract(NaiveNumber.ONE.promoteTo(param.getClass())))) != null && (check.compareTo((new NaiveNumber(0.1)).promoteTo(param.getClass()))) >= 0) {
-                if ((check = param.subtract(NaiveNumber.ONE.promoteTo(param.getClass()))) != null && check.signum() == 1) {
-                    param = param.divide(new NaiveNumber(2).promoteTo(param.getClass()));
+            while (FUNCTION_ABS.apply(param.subtract(NaiveNumber.ONE.promoteTo(param.getClass()))).compareTo(new NaiveNumber(0.1).promoteTo(param.getClass())) >= 0) {
+                if (param.subtract(NaiveNumber.ONE.promoteTo(param.getClass())).signum() == 1) {
+                    param = param.divide(fromInt(param.getClass(), 2));
                     powersOf2++;
-                    if ((check = param.subtract(NaiveNumber.ONE.promoteTo(param.getClass()))) == null || check.signum() != 1) {
+                    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 ((check = param.subtract(NaiveNumber.ONE.promoteTo(param.getClass()))) == null || check.signum() != 1) {
+                    if (param.subtract(NaiveNumber.ONE.promoteTo(param.getClass())).signum() != -1) {
                         break;
                         //No infinite loop for you.
                     }
                 }
             }
-            NumberInterface check2;
-            if (!Thread.currentThread().isInterrupted() && (check = getLog2(param)) != null && (check = check.multiply((new NaiveNumber(powersOf2).promoteTo(param.getClass())))) != null && (check2 = getLogPartialSum(param)) != null && (check = check.add(check2)) != null)
-                return check;
-            return null;
+            return getLog2(param).multiply((new NaiveNumber(powersOf2)).promoteTo(param.getClass())).add(getLogPartialSum(param));
         }
 
         /**
@@ -209,22 +188,16 @@ public class StandardPlugin extends Plugin {
          */
         private NumberInterface getLogPartialSum(NumberInterface x) {
 
-            if (Thread.currentThread().isInterrupted())
-                return null;
             NumberInterface maxError = getMaxError(x);
             x = x.subtract(NaiveNumber.ONE.promoteTo(x.getClass())); //Terms used are for log(x+1).
             NumberInterface currentNumerator = x, currentTerm = x, sum = x;
             int n = 1;
-            NumberInterface check;
-            while (!Thread.currentThread().isInterrupted() && (check = FUNCTION_ABS.apply(currentTerm)) != null && check.compareTo(maxError) > 0) {
+            while (FUNCTION_ABS.apply(currentTerm).compareTo(maxError) > 0) {
                 n++;
-                if ((currentNumerator = currentNumerator.multiply(x)) == null || (currentNumerator = currentNumerator.negate()) == null)
-                    return null;
+                currentNumerator = currentNumerator.multiply(x).negate();
                 currentTerm = currentNumerator.divide(new NaiveNumber(n).promoteTo(x.getClass()));
                 sum = sum.add(currentTerm);
             }
-            if (Thread.currentThread().isInterrupted())
-                return null;
             return sum;
         }
 
@@ -234,27 +207,21 @@ public class StandardPlugin extends Plugin {
          * @return the value of log(2) with the appropriate precision.
          */
         private NumberInterface getLog2(NumberInterface number) {
-            if (Thread.currentThread().isInterrupted())
-                return null;
             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 (!Thread.currentThread().isInterrupted() && a.compareTo(maxError) >= 1) {
+            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()));
-                NumberInterface check;
-                if (a == null || (check = a.add(b)) == null || (check = check.multiply(c)) == null || (sum = sum.add(check)) == null)
-                    return null;
+                sum = sum.add(a.add(b).multiply(c));
             }
-            if (Thread.currentThread().isInterrupted())
-                return null;
             return sum;
         }
     };
@@ -349,7 +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++;
@@ -378,15 +345,11 @@ public class StandardPlugin extends Plugin {
 
         @Override
         protected NumberInterface applyInternal(NumberInterface[] params) {
-            if (Thread.currentThread().isInterrupted()) return null;
-            else if (params[0].compareTo(NaiveNumber.ZERO.promoteTo(params[0].getClass())) == 0)
+            if (params[0].compareTo(NaiveNumber.ZERO.promoteTo(params[0].getClass())) == 0)
                 return NaiveNumber.ZERO.promoteTo(params[0].getClass());
             else if (params[1].compareTo(NaiveNumber.ZERO.promoteTo(params[0].getClass())) == 0)
                 return NaiveNumber.ONE.promoteTo(params[1].getClass());
-            FUNCTION_EXP.apply(FUNCTION_LN.apply(FUNCTION_ABS.apply(params[0])).multiply(params[1]));
-            NumberInterface check = FUNCTION_LN.apply(FUNCTION_ABS.apply(params[0]));
-            if(check == null) return null;
-            return FUNCTION_EXP.apply(check.multiply(params[1]));
+            return FUNCTION_EXP.apply(FUNCTION_LN.apply(FUNCTION_ABS.apply(params[0])).multiply(params[1]));
         }
     });
     /**
@@ -400,13 +363,13 @@ public class StandardPlugin extends Plugin {
 
         @Override
         protected NumberInterface applyInternal(NumberInterface[] params) {
-            NumberInterface pi = getPi(params[0].getClass());
-            NumberInterface twoPi = pi.multiply(new NaiveNumber(2).promoteTo(pi.getClass()));
+            NumberInterface pi = piFor(params[0].getClass());
+            NumberInterface twoPi = pi.multiply(fromInt(pi.getClass(), 2));
             NumberInterface theta = getSmallAngle(params[0], pi);
             //System.out.println(theta);
             if (theta.compareTo(pi.multiply(new NaiveNumber(1.5).promoteTo(twoPi.getClass()))) >= 0) {
                 theta = theta.subtract(twoPi);
-            } else if (theta.compareTo(pi.divide(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);
@@ -424,7 +387,7 @@ public class StandardPlugin extends Plugin {
 
         @Override
         protected NumberInterface applyInternal(NumberInterface[] params) {
-            return functionSin.apply(getPi(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]));
         }
     };
@@ -481,7 +444,7 @@ public class StandardPlugin extends Plugin {
 
         @Override
         protected NumberInterface applyInternal(NumberInterface[] params) {
-            return functionCos.apply(params[0]).divide(functionCos.apply(params[0]));
+            return functionCos.apply(params[0]).divide(functionSin.apply(params[0]));
         }
     };
 
@@ -512,7 +475,7 @@ 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());
     }
 
     /**
@@ -524,8 +487,6 @@ public class StandardPlugin extends Plugin {
      * @return a number of numClass with value n factorial.
      */
     public static NumberInterface factorial(Class<? extends NumberInterface> numberClass, int n) {
-        if (Thread.currentThread().isInterrupted())
-            return null;
         if (!FACTORIAL_LISTS.containsKey(numberClass)) {
             FACTORIAL_LISTS.put(numberClass, new ArrayList<>());
             FACTORIAL_LISTS.get(numberClass).add(NaiveNumber.ONE.promoteTo(numberClass));
@@ -533,12 +494,10 @@ public class StandardPlugin extends Plugin {
         }
         ArrayList<NumberInterface> list = FACTORIAL_LISTS.get(numberClass);
         if (n >= list.size()) {
-            while (!Thread.currentThread().isInterrupted() && list.size() < n + 16) {
+            while (list.size() < n + 16) {
                 list.add(list.get(list.size() - 1).multiply(new NaiveNumber(list.size()).promoteTo(numberClass)));
             }
         }
-        if (Thread.currentThread().isInterrupted())
-            return null;
         return list.get(n);
     }
 
@@ -577,26 +536,20 @@ public class StandardPlugin extends Plugin {
         return theta;
     }
 
-    public static NumberInterface intPow(NumberInterface number, Class<? extends NumberInterface> numberClass, NumberInterface exponent) {
-        if (Thread.currentThread().isInterrupted())
-            return null;
-        if (exponent.compareTo((new NaiveNumber(0)).promoteTo(numberClass)) == 0) {
-            return (new NaiveNumber(1)).promoteTo(numberClass);
+    /**
+     * 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<>());
         }
-        boolean takeReciprocal = exponent.compareTo((new NaiveNumber(0)).promoteTo(numberClass)) < 0;
-        exponent = FUNCTION_ABS.apply(exponent);
-        NumberInterface power = number;
-        for (NumberInterface currentExponent = (new NaiveNumber(1)).promoteTo(numberClass); currentExponent.compareTo(exponent) < 0; currentExponent = currentExponent.add((new NaiveNumber(1)).promoteTo(numberClass))) {
-            power = power.multiply(number);
-            if (Thread.currentThread().isInterrupted())
-                return null;
+        if(!integerValues.get(numType).containsKey(n)){
+            integerValues.get(numType).put(n, new NaiveNumber(n).promoteTo(numType));
         }
-        if (takeReciprocal) {
-            power = (new NaiveNumber(1)).promoteTo(numberClass).divide(power);
-        }
-        if (Thread.currentThread().isInterrupted())
-            return null;
-        return power;
+        return integerValues.get(numType).get(n);
     }
 
     @Override

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

@@ -92,15 +92,10 @@ public class BinaryNode extends TreeNode {
 
     @Override
     public <T> T reduce(Reducer<T> reducer) {
-        if (Thread.currentThread().isInterrupted())
-            return null;
         T leftReduce = left.reduce(reducer);
         T rightReduce = right.reduce(reducer);
         if (leftReduce == null || rightReduce == null) return null;
-        T a = reducer.reduceNode(this, leftReduce, rightReduce);
-        if (Thread.currentThread().isInterrupted())
-            return null;
-        return a;
+        return reducer.reduceNode(this, leftReduce, rightReduce);
     }
 
     @Override

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

@@ -62,17 +62,12 @@ public class FunctionNode extends TreeNode {
 
     @Override
     public <T> T reduce(Reducer<T> reducer) {
-        if (Thread.currentThread().isInterrupted())
-            return null;
         Object[] reducedChildren = new Object[children.size()];
         for (int i = 0; i < reducedChildren.length; i++) {
             reducedChildren[i] = children.get(i).reduce(reducer);
-            if (Thread.currentThread().isInterrupted() || reducedChildren[i] == null) return null;
+            if (reducedChildren[i] == null) return null;
         }
-        T a = reducer.reduceNode(this, reducedChildren);
-        if (Thread.currentThread().isInterrupted())
-            return null;
-        return a;
+        return reducer.reduceNode(this, reducedChildren);
     }
 
     @Override

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

@@ -33,14 +33,9 @@ public class UnaryNode extends TreeNode {
 
     @Override
     public <T> T reduce(Reducer<T> reducer) {
-        if (Thread.currentThread().isInterrupted())
-            return null;
         Object reducedChild = applyTo.reduce(reducer);
         if (reducedChild == null) return null;
-        T a = reducer.reduceNode(this, reducedChild);
-        if (Thread.currentThread().isInterrupted())
-            return null;
-        return a;
+        return reducer.reduceNode(this, reducedChild);
     }
 
     /**

src/main/resources/abacus.fxml

@@ -35,7 +35,7 @@
                             <Button fx:id="inputButton" text="Calculate" maxWidth="Infinity"
                                     onAction="#performCalculation"/>
                             <Button fx:id="stopButton" text="Stop" maxWidth="Infinity"
-                                    onAction="#stopCalculation"/>
+                                    onAction="#performStop" disable="true"/>
                         </VBox>
                     </bottom>
                 </BorderPane>
@@ -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