Add comments and clean some code.

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

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

@@ -2,12 +2,12 @@ package org.nwapw.abacus;
 
 import org.nwapw.abacus.config.Configuration;
 import org.nwapw.abacus.fx.AbacusApplication;
-import org.nwapw.abacus.number.NaiveNumber;
 import org.nwapw.abacus.number.NumberInterface;
 import org.nwapw.abacus.parsing.LexerTokenizer;
 import org.nwapw.abacus.parsing.ShuntingYardParser;
 import org.nwapw.abacus.parsing.TreeBuilder;
 import org.nwapw.abacus.plugin.ClassFinder;
+import org.nwapw.abacus.plugin.NumberImplementation;
 import org.nwapw.abacus.plugin.PluginManager;
 import org.nwapw.abacus.plugin.StandardPlugin;
 import org.nwapw.abacus.tree.NumberReducer;
@@ -15,7 +15,6 @@ import org.nwapw.abacus.tree.TreeNode;
 
 import java.io.File;
 import java.io.IOException;
-import java.lang.reflect.InvocationTargetException;
 
 /**
  * The main calculator class. This is responsible
@@ -24,10 +23,7 @@ import java.lang.reflect.InvocationTargetException;
  */
 public class Abacus {
 
-    /**
-     * The default implementation to use for the number representation.
-     */
-    public static final Class<? extends NumberInterface> DEFAULT_NUMBER = NaiveNumber.class;
+    public static final NumberImplementation DEFAULT_IMPLEMENTATION = StandardPlugin.IMPLEMENTATION_NAIVE;
     /**
      * The file used for saving and loading configuration.
      */
@@ -57,7 +53,7 @@ public class Abacus {
      * Creates a new instance of the Abacus calculator.
      */
     public Abacus() {
-        pluginManager = new PluginManager();
+        pluginManager = new PluginManager(this);
         numberReducer = new NumberReducer(this);
         configuration = new Configuration(CONFIG_FILE);
         configuration.saveTo(CONFIG_FILE);
@@ -147,15 +143,10 @@ public class Abacus {
      * @return the resulting number.
      */
     public NumberInterface numberFromString(String numberString) {
-        Class<? extends NumberInterface> toInstantiate =
-                pluginManager.numberFor(configuration.getNumberImplementation());
-        if (toInstantiate == null) toInstantiate = DEFAULT_NUMBER;
+        NumberImplementation toInstantiate =
+                pluginManager.numberImplementationFor(configuration.getNumberImplementation());
+        if (toInstantiate == null) toInstantiate = DEFAULT_IMPLEMENTATION;
 
-        try {
-            return toInstantiate.getConstructor(String.class).newInstance(numberString);
-        } catch (InstantiationException | IllegalAccessException | NoSuchMethodException | InvocationTargetException e) {
-            e.printStackTrace();
-        }
-        return null;
+        return toInstantiate.instanceForString(numberString);
     }
 }

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

@@ -5,6 +5,9 @@ import com.moandjiezana.toml.TomlWriter;
 
 import java.io.File;
 import java.io.IOException;
+import java.util.Arrays;
+import java.util.HashSet;
+import java.util.Set;
 
 /**
  * The configuration object that stores
@@ -12,26 +15,38 @@ import java.io.IOException;
  */
 public class Configuration {
 
+    /**
+     * The defaults TOML string.
+     */
+    private static final String DEFAULT_CONFIG =
+            "numberImplementation = \"naive\"\n" +
+            "disabledPlugins = []";
+    /**
+     * The defaults TOML object, parsed from the string.
+     */
+    private static final Toml DEFAULT_TOML = new Toml().read(DEFAULT_CONFIG);
     /**
      * The TOML writer used to write this configuration to a file.
      */
     private static final TomlWriter TOML_WRITER = new TomlWriter();
-    /**
-     * The TOML reader used to load this config from a file.
-     */
-    private static final Toml TOML_READER = new Toml();
 
     /**
      * The implementation of the number that should be used.
      */
-    private String numberImplementation = "naive";
+    private String numberImplementation = "<default>";
+    /**
+     * The list of disabled plugins in this Configuration.
+     */
+    private Set<String> disabledPlugins = new HashSet<>();
 
     /**
      * Creates a new configuration with the given values.
      * @param numberImplementation the number implementation, like "naive" or "precise"
+     * @param disabledPlugins the list of disabled plugins.
      */
-    public Configuration(String numberImplementation){
+    public Configuration(String numberImplementation, String[] disabledPlugins){
         this.numberImplementation = numberImplementation;
+        this.disabledPlugins.addAll(Arrays.asList(disabledPlugins));
     }
 
     /**
@@ -40,7 +55,7 @@ public class Configuration {
      */
     public Configuration(File fromFile){
         if(!fromFile.exists()) return;
-        copyFrom(TOML_READER.read(fromFile).to(Configuration.class));
+        copyFrom(new Toml(DEFAULT_TOML).read(fromFile).to(Configuration.class));
     }
 
     /**
@@ -49,6 +64,7 @@ public class Configuration {
      */
     public void copyFrom(Configuration otherConfiguration){
         this.numberImplementation = otherConfiguration.numberImplementation;
+        this.disabledPlugins.addAll(otherConfiguration.disabledPlugins);
     }
 
     /**
@@ -80,4 +96,13 @@ public class Configuration {
     public void setNumberImplementation(String numberImplementation) {
         this.numberImplementation = numberImplementation;
     }
+
+    /**
+     * Gets the list of disabled plugins.
+     * @return the list of disabled plugins.
+     */
+    public Set<String> getDisabledPlugins() {
+        return disabledPlugins;
+    }
+
 }

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

@@ -1,10 +1,6 @@
 package org.nwapw.abacus.function;
 
-import org.nwapw.abacus.number.NaiveNumber;
 import org.nwapw.abacus.number.NumberInterface;
-import org.nwapw.abacus.number.PreciseNumber;
-
-import java.util.HashMap;
 
 /**
  * A function that operates on one or more
@@ -12,15 +8,6 @@ import java.util.HashMap;
  */
 public abstract class Function {
 
-    /**
-     * A map to correctly promote different number implementations to each other.
-     */
-    private static final HashMap<Class<? extends NumberInterface>, Integer> priorityMap =
-            new HashMap<Class<? extends NumberInterface>, Integer>() {{
-                put(NaiveNumber.class, 0);
-                put(PreciseNumber.class, 1);
-            }};
-
     /**
      * Checks whether the given params will work for the given function.
      *

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

@@ -1,23 +1,42 @@
 package org.nwapw.abacus.fx;
 
-import javafx.application.Platform;
 import javafx.collections.FXCollections;
 import javafx.collections.ObservableList;
 import javafx.fxml.FXML;
 import javafx.scene.control.*;
+import javafx.scene.control.cell.CheckBoxListCell;
 import javafx.scene.text.Text;
 import javafx.util.Callback;
+import javafx.util.StringConverter;
 import org.nwapw.abacus.Abacus;
+import org.nwapw.abacus.config.Configuration;
 import org.nwapw.abacus.number.NumberInterface;
+import org.nwapw.abacus.plugin.PluginListener;
+import org.nwapw.abacus.plugin.PluginManager;
 import org.nwapw.abacus.tree.TreeNode;
 
+import java.util.Set;
+
 
 /**
  * The controller for the abacus FX UI, responsible
  * for all the user interaction.
  */
-public class AbacusController {
+public class AbacusController implements PluginListener {
 
+    /**
+     * The title for the apply alert dialog.
+     */
+    private static final String APPLY_MSG_TITLE = "\"Apply\" Needed";
+    /**
+     * The text for the header of the apply alert dialog.
+     */
+    private static final String APPLY_MSG_HEADER = "The settings have not been applied.";
+    /**
+     * The text for the dialog that is shown if settings haven't been applied.
+     */
+    private static final String APPLY_MSG_TEXT = "You have made changes to the configuration, however, you haven't pressed \"Apply\". " +
+                "The changes to the configuration will not be present in the calculator until \"Apply\" is pressed.";
     /**
      * Constant string that is displayed if the text could not be lexed or parsed.
      */
@@ -26,10 +45,13 @@ public class AbacusController {
      * Constant string that is displayed if the tree could not be reduced.
      */
     private static final String ERR_EVAL = "Evaluation Error";
-    /**
-     * Constant string that is displayed if the calculations are stopped before they are done.
-     */
-    private static final String ERR_STOP = "Stopped";
+
+    @FXML
+    private TabPane coreTabPane;
+    @FXML
+    private Tab calculateTab;
+    @FXML
+    private Tab settingsTab;
     @FXML
     private TableView<HistoryModel> historyTable;
     @FXML
@@ -46,6 +68,8 @@ public class AbacusController {
     private Button inputButton;
     @FXML
     private ComboBox<String> numberImplementationBox;
+    @FXML
+    private ListView<ToggleablePlugin> enabledPluginView;
 
     /**
      * The list of history entries, created by the users.
@@ -59,109 +83,158 @@ public class AbacusController {
     private ObservableList<String> numberImplementationOptions;
 
     /**
-     * Thread used for calculating.
+     * 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 Thread calcThread;
+    private ObservableList<ToggleablePlugin> enabledPlugins;
 
     /**
-     * Checks whether the calculator is calculating.
+     * The abacus instance used for changing the plugin configuration.
      */
-    private boolean calculating;
-
-    /**
-     * Seconds delayed for timer;
-     */
-    private double delay = 0;
     private Abacus abacus;
 
+    /**
+     * Boolean which represents whether changes were made to the configuration.
+     */
+    private boolean changesMade;
+    /**
+     * Whether an alert about changes to the configuration was already shown.
+     */
+    private boolean reloadAlertShown;
+    /**
+     * The alert shown when a press to "apply" is needed.
+     */
+    private Alert reloadAlert;
+
+    /**
+     * Alerts the user if the changes they made
+     * have not yet been applied.
+     */
+    private void alertIfApplyNeeded(boolean ignorePrevious){
+        if(changesMade && (!reloadAlertShown || ignorePrevious)) {
+            reloadAlertShown = true;
+            reloadAlert.showAndWait();
+        }
+    }
+
     @FXML
     public void initialize(){
         Callback<TableColumn<HistoryModel, String>, TableCell<HistoryModel, String>> cellFactory =
                 param -> new CopyableCell<>();
+        Callback<ListView<ToggleablePlugin>, ListCell<ToggleablePlugin>> pluginCellFactory =
+                param -> new CheckBoxListCell<>(ToggleablePlugin::enabledProperty, new StringConverter<ToggleablePlugin>() {
+                    @Override
+                    public String toString(ToggleablePlugin object) {
+                        return object.getClassName().substring(object.getClassName().lastIndexOf('.') + 1);
+                    }
+
+                    @Override
+                    public ToggleablePlugin fromString(String string) {
+                        return new ToggleablePlugin(true, string);
+                    }
+                });
 
         historyData = FXCollections.observableArrayList();
         historyTable.setItems(historyData);
         numberImplementationOptions = FXCollections.observableArrayList();
         numberImplementationBox.setItems(numberImplementationOptions);
-        numberImplementationBox.valueProperty().addListener((observable, oldValue, newValue)
-                -> {
-            abacus.getConfiguration().setNumberImplementation(newValue);
-            abacus.getConfiguration().saveTo(Abacus.CONFIG_FILE);
-        });
+        numberImplementationBox.getSelectionModel().selectedIndexProperty().addListener(e -> changesMade = true);
         historyTable.getSelectionModel().setCellSelectionEnabled(true);
+        enabledPlugins = FXCollections.observableArrayList();
+        enabledPluginView.setItems(enabledPlugins);
+        enabledPluginView.setCellFactory(pluginCellFactory);
         inputColumn.setCellFactory(cellFactory);
         inputColumn.setCellValueFactory(cell -> cell.getValue().inputProperty());
         parsedColumn.setCellFactory(cellFactory);
         parsedColumn.setCellValueFactory(cell -> cell.getValue().parsedProperty());
         outputColumn.setCellFactory(cellFactory);
         outputColumn.setCellValueFactory(cell -> cell.getValue().outputProperty());
+        coreTabPane.getSelectionModel().selectedItemProperty().addListener((observable, oldValue, newValue) -> {
+            if(oldValue.equals(settingsTab)) alertIfApplyNeeded(true);
+        });
 
         abacus = new Abacus();
-        numberImplementationOptions.addAll(abacus.getPluginManager().getAllNumbers());
-        String actualImplementation = abacus.getConfiguration().getNumberImplementation();
-        String toSelect = (numberImplementationOptions.contains(actualImplementation)) ? actualImplementation : "naive";
-        numberImplementationBox.getSelectionModel().select(toSelect);
+        abacus.getPluginManager().addListener(this);
+        abacus.getPluginManager().reload();
+
+        changesMade = false;
+        reloadAlertShown = false;
+
+        reloadAlert = new Alert(Alert.AlertType.WARNING);
+        reloadAlert.setTitle(APPLY_MSG_TITLE);
+        reloadAlert.setHeaderText(APPLY_MSG_HEADER);
+        reloadAlert.setContentText(APPLY_MSG_TEXT);
     }
 
     @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()));
+        inputButton.setDisable(true);
+        TreeNode constructedTree = abacus.parseString(inputField.getText());
+        if(constructedTree == null){
+            outputText.setText(ERR_SYNTAX);
+            inputButton.setDisable(false);
+            return;
+        }
+        NumberInterface evaluatedNumber = abacus.evaluateTree(constructedTree);
+        if(evaluatedNumber == null){
+            outputText.setText(ERR_EVAL);
+            inputButton.setDisable(false);
+            return;
+        }
+        outputText.setText(evaluatedNumber.toString());
+        historyData.add(new HistoryModel(inputField.getText(), constructedTree.toString(), evaluatedNumber.toString()));
 
-                        historyData.add(new HistoryModel(inputField.getText(), constructedTree.toString(), evaluatedNumber.toString()));
+        inputButton.setDisable(false);
+        inputField.setText("");
+    }
 
-                        Platform.runLater(() -> inputButton.setDisable(false));
-                        Platform.runLater(() -> inputField.setText(""));
-                    }
-                }
-                calculating = false;
-            }
-        };
-        if(!calculating) {
-                calcThread = new Thread(calculator);
-                calcThread.setName("calcThread");
-                calcThread.start();
+    @FXML
+    private void performSaveAndReload(){
+        performSave();
+        performReload();
+        changesMade = false;
+        reloadAlertShown = false;
+    }
+
+    @FXML
+    private void performReload(){
+        alertIfApplyNeeded(true);
+        abacus.getPluginManager().reload();
+    }
+
+    @FXML
+    private void performSave(){
+        Configuration configuration = abacus.getConfiguration();
+        configuration.setNumberImplementation(numberImplementationBox.getSelectionModel().getSelectedItem());
+        Set<String> disabledPlugins = configuration.getDisabledPlugins();
+        disabledPlugins.clear();
+        for(ToggleablePlugin pluginEntry : enabledPlugins){
+            if(!pluginEntry.isEnabled()) disabledPlugins.add(pluginEntry.getClassName());
+        }
+        configuration.saveTo(Abacus.CONFIG_FILE);
+        changesMade = false;
+        reloadAlertShown = false;
+    }
+
+    @Override
+    public void onLoad(PluginManager manager) {
+        Configuration configuration = abacus.getConfiguration();
+        Set<String> disabledPlugins = configuration.getDisabledPlugins();
+        numberImplementationOptions.addAll(abacus.getPluginManager().getAllNumberImplementations());
+        String actualImplementation = configuration.getNumberImplementation();
+        String toSelect = (numberImplementationOptions.contains(actualImplementation)) ? actualImplementation : "<default>";
+        numberImplementationBox.getSelectionModel().select(toSelect);
+        for(Class<?> pluginClass : abacus.getPluginManager().getLoadedPluginClasses()){
+            String fullName = pluginClass.getName();
+            ToggleablePlugin plugin = new ToggleablePlugin(!disabledPlugins.contains(fullName), fullName);
+            plugin.enabledProperty().addListener(e -> changesMade = true);
+            enabledPlugins.add(plugin);
         }
     }
-    @FXML
-    private void stopCalculation(){
-        calcThread.interrupt();
-        calculating = false;
-        //Platform.runLater(() ->inputButton.setDisable(false));
-    }
 
+    @Override
+    public void onUnload(PluginManager manager) {
+        enabledPlugins.clear();
+        numberImplementationOptions.clear();
+    }
 }

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

@@ -0,0 +1,56 @@
+package org.nwapw.abacus.fx;
+
+import javafx.beans.property.BooleanProperty;
+import javafx.beans.property.SimpleBooleanProperty;
+
+/**
+ * Class that represents an entry in the plugin check box list.
+ * The changes from this property are written to the config on application.
+ */
+public class ToggleablePlugin {
+
+    /**
+     * The property that determines whether the plugin will be enabled.
+     */
+    private final BooleanProperty enabled;
+    /**
+     * The name of the class this entry toggles.
+     */
+    private final String className;
+
+    /**
+     * Creates a new toggleable plugin with the given properties.
+     * @param enabled the enabled / disabled state at the beginning.
+     * @param className the name of the class this plugin toggles.
+     */
+    public ToggleablePlugin(boolean enabled, String className){
+        this.enabled = new SimpleBooleanProperty();
+        this.enabled.setValue(enabled);
+        this.className = className;
+    }
+
+    /**
+     * Gets the enabled property of this plugin.
+     * @return the enabled property.
+     */
+    public BooleanProperty enabledProperty() {
+        return enabled;
+    }
+
+    /**
+     * Checks if this plugin entry should be enabled.
+     * @return whether this plugin will be enabled.
+     */
+    public boolean isEnabled() {
+        return enabled.get();
+    }
+
+    /**
+     * Gets the class name this plugin toggles.
+     * @return the class name that should be disabled.
+     */
+    public String getClassName() {
+        return className;
+    }
+
+}

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

@@ -94,8 +94,23 @@ public class NaiveNumber implements NumberInterface {
     }
 
     @Override
-    public int ceiling() {
-        return (int) Math.ceil(value);
+    public NumberInterface ceiling() {
+        return new NaiveNumber(Math.ceil(value));
+    }
+
+    @Override
+    public NumberInterface floor() {
+        return new NaiveNumber(Math.floor(value));
+    }
+
+    @Override
+    public NumberInterface fractionalPart() {
+        return new NaiveNumber(value - Math.floor(value));
+    }
+
+    @Override
+    public int intValue() {
+        return (int)value;
     }
 
     @Override

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

@@ -83,7 +83,26 @@ public interface NumberInterface {
      * Returns the least integer greater than or equal to the number.
      * @return the least integer >= the number, if int can hold the value.
      */
-    int ceiling();
+    NumberInterface ceiling();
+
+    /**
+     * Return the greatest integer less than or equal to the number.
+     * @return the greatest int >= the number, if int can hold the value.
+     */
+    NumberInterface floor();
+
+    /**
+     * Returns the fractional part of the number.
+     * @return the fractional part of the number.
+     */
+    NumberInterface fractionalPart();
+
+    /**
+     * Returns the integer representation of this number, discarding any fractional part,
+     * if int can hold the value.
+     * @return
+     */
+    int intValue();
 
     /**
      * Promotes this class to another number class.

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

@@ -12,15 +12,15 @@ public class PreciseNumber implements NumberInterface {
     /**
      * The number one.
      */
-    static final PreciseNumber ONE = new PreciseNumber(BigDecimal.ONE);
+    public static final PreciseNumber ONE = new PreciseNumber(BigDecimal.ONE);
     /**
      * The number zero.
      */
-    static final PreciseNumber ZERO = new PreciseNumber(BigDecimal.ZERO);
+    public static final PreciseNumber ZERO = new PreciseNumber(BigDecimal.ZERO);
     /**
      * The number ten.
      */
-    static final PreciseNumber TEN = new PreciseNumber(BigDecimal.TEN);
+    public static final PreciseNumber TEN = new PreciseNumber(BigDecimal.TEN);
 
     /**
      * The value of the PreciseNumber.
@@ -99,8 +99,38 @@ public class PreciseNumber implements NumberInterface {
     }
 
     @Override
-    public int ceiling() {
-        return (int) Math.ceil(value.doubleValue());
+    public NumberInterface ceiling() {
+        String str = value.toPlainString();
+        int decimalIndex = str.indexOf('.');
+        if(decimalIndex != -1){
+            return this.floor().add(ONE);
+        }
+        return this;
+    }
+
+    @Override
+    public NumberInterface floor() {
+        String str = value.toPlainString();
+        int decimalIndex = str.indexOf('.');
+        if(decimalIndex != -1){
+            return new PreciseNumber(str.substring(0, decimalIndex));
+        }
+        return this;
+    }
+
+    @Override
+    public NumberInterface fractionalPart() {
+        String str = value.toPlainString();
+        int decimalIndex = str.indexOf('.');
+        if(decimalIndex != -1){
+            return new PreciseNumber(str.substring(decimalIndex + 1));
+        }
+        return ZERO;
+    }
+
+    @Override
+    public int intValue() {
+        return value.intValue();
     }
 
     @Override

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

@@ -89,7 +89,7 @@ public class ShuntingYardParser implements Parser<Match<TokenType>>, PluginListe
                     if (!(otherMatchType == TokenType.OP || otherMatchType == TokenType.FUNCTION)) break;
 
                     if (otherMatchType == TokenType.OP) {
-                        int otherPrecedence = precedenceMap.get(match.getContent());
+                        int otherPrecedence = precedenceMap.get(otherMatch.getContent());
                         if (otherPrecedence < precedence ||
                                 (associativity == OperatorAssociativity.RIGHT && otherPrecedence == precedence)) {
                             break;

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

@@ -0,0 +1,75 @@
+package org.nwapw.abacus.plugin;
+
+import org.nwapw.abacus.number.NumberInterface;
+
+import java.util.HashMap;
+import java.util.Map;
+import java.util.function.Function;
+
+/**
+ * A class that holds data about a number implementation.
+ */
+public abstract class NumberImplementation {
+
+    /**
+     * The list of paths through which this implementation can be promoted.
+     */
+    protected Map<Class<? extends NumberInterface>, Function<NumberInterface, NumberInterface>> promotionPaths;
+    /**
+     * The implementation class for this implementation.
+     */
+    private Class<? extends NumberInterface> implementation;
+    /**
+     * The priority of converting into this number implementation.
+     */
+    private int priority;
+
+    /**
+     * 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.
+     */
+    public NumberImplementation(Class<? extends NumberInterface> implementation, int priority){
+        this.implementation = implementation;
+        this.priority = priority;
+        promotionPaths = new HashMap<>();
+    }
+
+    /**
+     * Gets the list of all promotion paths this implementation can take.
+     * @return the map of documentation paths.
+     */
+    public final Map<Class<? extends NumberInterface>, Function<NumberInterface, NumberInterface>> getPromotionPaths(){
+        return promotionPaths;
+    }
+
+    /**
+     * Gets the implementation class used by this implementation.
+     * @return the implementation class.
+     */
+    public final Class<? extends NumberInterface> getImplementation(){
+        return implementation;
+    }
+
+    /**
+     * Gets the priority of this number implementation.
+     * @return the priority.
+     */
+    public final int getPriority(){
+        return priority;
+    }
+
+    /**
+     * Abstract function to create a new instance from a string.
+     * @param string the string to create a number from.
+     * @return the resulting number.
+     */
+    public abstract NumberInterface instanceForString(String string);
+
+    /**
+     * Get the instance of pi with the given implementation.
+     * @return pi
+     */
+    public abstract NumberInterface instanceForPi();
+
+}

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

@@ -26,9 +26,9 @@ public abstract class Plugin {
      */
     private Map<String, Operator> operators;
     /**
-     * A hash map of operators mapped to their string names.
+     * The map of the number implementations this plugin provides.
      */
-    private Map<String, Class<? extends NumberInterface>> numbers;
+    private Map<String, NumberImplementation> numberImplementations;
     /**
      * The plugin manager in which to search for functions
      * not inside this package,
@@ -51,7 +51,7 @@ public abstract class Plugin {
         this.manager = manager;
         functions = new HashMap<>();
         operators = new HashMap<>();
-        numbers = new HashMap<>();
+        numberImplementations = new HashMap<>();
         enabled = false;
     }
 
@@ -74,12 +74,12 @@ public abstract class Plugin {
     }
 
     /**
-     * Gets the list of all numbers provided by this plugin.
+     * Gets the list of number implementations provided by this plugin.
      *
-     * @return the list of registered numbers.
+     * @return the list of registered number implementations.
      */
-    public final Set<String> providedNumbers() {
-        return numbers.keySet();
+    public final Set<String> providedNumberImplementations(){
+        return numberImplementations.keySet();
     }
 
     /**
@@ -103,13 +103,13 @@ public abstract class Plugin {
     }
 
     /**
-     * Gets the class under the given name.
+     * Gets the number implementation under the given name.
      *
-     * @param numberName the name of the class.
-     * @return the class, or null if the plugin doesn't provide it.
+     * @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 Class<? extends NumberInterface> getNumber(String numberName) {
-        return numbers.get(numberName);
+    public final NumberImplementation getNumberImplementation(String name){
+        return numberImplementations.get(name);
     }
 
     /**
@@ -158,16 +158,13 @@ public abstract class Plugin {
     }
 
     /**
-     * To be used in load(). Registers a number class
-     * with the plugin internally, which makes it possible
-     * for the user to select it as an "implementation" for the
-     * number that they would like to use.
-     *
-     * @param name       the name to register it under.
-     * @param toRegister the class to register.
+     * To be used in load(). Registers a new number implementation with the plugin.
+     * This makes it accessible to the plugin manager.
+     * @param name the name of the implementation.
+     * @param implementation the actual implementation class to register.
      */
-    protected final void registerNumber(String name, Class<? extends NumberInterface> toRegister) {
-        numbers.put(name, toRegister);
+    protected final void registerNumberImplementation(String name, NumberImplementation implementation){
+        numberImplementations.put(name, implementation);
     }
 
     /**
@@ -194,6 +191,30 @@ public abstract class Plugin {
         return manager.operatorFor(name);
     }
 
+    /**
+     * Searches the PluginManager for the given number implementation
+     * name. This can be used by the plugins internally in order to find
+     * implementations that they do not provide.
+     *
+     * @param name the name for which to search.
+     * @return the resulting number implementation, or null if none was found.
+     */
+    protected final NumberImplementation numberImplementationFor(String name){
+        return manager.numberImplementationFor(name);
+    }
+
+    /**
+     * Searches the plugin manager for a Pi value for the given number implementation.
+     * This is done so that number implementations with various degrees of precision
+     * can provide their own pi values, without losing said precision by
+     * promoting NaiveNumbers.
+     * @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){
+        return manager.piFor(forClass);
+    }
+
     /**
      * Abstract method to be overridden by plugin implementation, in which the plugins
      * are supposed to register the functions they provide and do any other

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

@@ -1,5 +1,6 @@
 package org.nwapw.abacus.plugin;
 
+import org.nwapw.abacus.Abacus;
 import org.nwapw.abacus.function.Function;
 import org.nwapw.abacus.function.Operator;
 import org.nwapw.abacus.number.NumberInterface;
@@ -32,10 +33,19 @@ public class PluginManager {
      */
     private Map<String, Operator> cachedOperators;
     /**
-     * List of registered number implementations that have
+     * The list of number implementations that have
      * been cached, that is, found in a plugin and returned.
      */
-    private Map<String, Class<? extends NumberInterface>> cachedNumbers;
+    private Map<String, NumberImplementation> cachedNumberImplementations;
+    /**
+     * The list of number implementations that have been
+     * found by their implementation class.
+     */
+    private Map<Class<? extends NumberInterface>, NumberImplementation> cachedInterfaceImplementations;
+    /**
+     * 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.
      */
@@ -45,26 +55,34 @@ public class PluginManager {
      */
     private Set<String> allOperators;
     /**
-     * List of all numbers loaded by the plugins.
+     * List of all the number implementations loaded by the plugins.
      */
-    private Set<String> allNumbers;
+    private Set<String> allNumberImplementations;
     /**
      * The list of plugin listeners attached to this instance.
      */
     private Set<PluginListener> listeners;
+    /**
+     * The abacus instance used to access other
+     * components of the application.
+     */
+    private Abacus abacus;
 
     /**
      * Creates a new plugin manager.
      */
-    public PluginManager() {
+    public PluginManager(Abacus abacus) {
+        this.abacus = abacus;
         loadedPluginClasses = new HashSet<>();
         plugins = new HashSet<>();
         cachedFunctions = new HashMap<>();
         cachedOperators = new HashMap<>();
-        cachedNumbers = new HashMap<>();
+        cachedNumberImplementations = new HashMap<>();
+        cachedInterfaceImplementations = new HashMap<>();
+        cachedPi = new HashMap<>();
         allFunctions = new HashSet<>();
         allOperators = new HashSet<>();
-        allNumbers = new HashSet<>();
+        allNumberImplementations = new HashSet<>();
         listeners = new HashSet<>();
     }
 
@@ -80,12 +98,13 @@ public class PluginManager {
      * @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.
      */
-    private static <T> T searchCached(Collection<Plugin> plugins, Map<String, T> cache,
-                                      java.util.function.Function<Plugin, Set<String>> setFunction,
-                                      java.util.function.BiFunction<Plugin, String, T> getFunction,
-                                      String name) {
+    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;
@@ -121,13 +140,51 @@ public class PluginManager {
     }
 
     /**
-     * Gets a numer implementation under the given name.
-     *
+     * Gets the number implementation under the given name.
      * @param name the name of the implementation.
-     * @return the implementation class
+     * @return the implementation.
      */
-    public Class<? extends NumberInterface> numberFor(String name) {
-        return searchCached(plugins, cachedNumbers, Plugin::providedNumbers, Plugin::getNumber, name);
+    public NumberImplementation numberImplementationFor(String name){
+        return searchCached(plugins, cachedNumberImplementations, Plugin::providedNumberImplementations,
+                Plugin::getNumberImplementation, name);
+    }
+
+    /**
+     * Gets the number implementation for the given implementation class.
+     * @param name the class for which to find the implementation.
+     * @return the implementation.
+     */
+    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;
+                }
+            }
+        }
+        cachedInterfaceImplementations.put(name, toReturn);
+        return toReturn;
+    }
+
+    /**
+     * Gets the mathematical constant pi for the given implementation class.
+     * @param forClass the class for which to find pi.
+     * @return pi
+     */
+    public NumberInterface piFor(Class<? extends NumberInterface> forClass){
+        if(cachedPi.containsKey(forClass)) return cachedPi.get(forClass);
+        NumberImplementation implementation = interfaceImplementationFor(forClass);
+        NumberInterface generatedPi = null;
+        if(implementation != null){
+            generatedPi = implementation.instanceForPi();
+        }
+        cachedPi.put(forClass, generatedPi);
+        return generatedPi;
     }
 
     /**
@@ -160,11 +217,16 @@ public class PluginManager {
      * Loads all the plugins in the PluginManager.
      */
     public void load() {
-        for (Plugin plugin : plugins) plugin.enable();
+        Set<String> disabledPlugins = abacus.getConfiguration().getDisabledPlugins();
         for (Plugin plugin : plugins) {
+            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());
-            allNumbers.addAll(plugin.providedNumbers());
+            allNumberImplementations.addAll(plugin.providedNumberImplementations());
         }
         listeners.forEach(e -> e.onLoad(this));
     }
@@ -173,10 +235,20 @@ public class PluginManager {
      * Unloads all the plugins in the PluginManager.
      */
     public void unload() {
-        for (Plugin plugin : plugins) plugin.disable();
+        listeners.forEach(e -> e.onUnload(this));
+        Set<String> disabledPlugins = abacus.getConfiguration().getDisabledPlugins();
+        for (Plugin plugin : plugins) {
+            if(disabledPlugins.contains(plugin.getClass().getName())) continue;
+            plugin.disable();
+        }
+        cachedFunctions.clear();
+        cachedOperators.clear();
+        cachedNumberImplementations.clear();
+        cachedInterfaceImplementations.clear();
+        cachedPi.clear();
         allFunctions.clear();
         allOperators.clear();
-        allNumbers.clear();
+        allNumberImplementations.clear();
         listeners.forEach(e -> e.onUnload(this));
     }
 
@@ -185,7 +257,7 @@ public class PluginManager {
      */
     public void reload() {
         unload();
-        reload();
+        load();
     }
 
     /**
@@ -207,12 +279,12 @@ public class PluginManager {
     }
 
     /**
-     * Gets all the number implementations loaded by the Plugin Manager
+     * Gets all the number implementations loaded by the Plugin Manager.
      *
-     * @return the set of all implementations that were loaded
+     * @return the set of all implementations that were loaded.
      */
-    public Set<String> getAllNumbers() {
-        return allNumbers;
+    public Set<String> getAllNumberImplementations(){
+        return allNumberImplementations;
     }
 
     /**
@@ -233,4 +305,12 @@ public class PluginManager {
         listeners.remove(listener);
     }
 
+    /**
+     * Gets a list of all the plugin class files that have been
+     * added to the plugin manager.
+     * @return the list of all the added plugin classes.
+     */
+    public Set<Class<?>> getLoadedPluginClasses() {
+        return loadedPluginClasses;
+    }
 }

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

@@ -18,7 +18,7 @@ import java.util.function.BiFunction;
  */
 public class StandardPlugin extends Plugin {
 
-    private static HashMap<Class<? extends NumberInterface>, ArrayList<NumberInterface>> factorialLists = new HashMap<Class<? extends NumberInterface>, ArrayList<NumberInterface>>();
+    private static final HashMap<Class<? extends NumberInterface>, ArrayList<NumberInterface>> FACTORIAL_LISTS = new HashMap<>();
 
     /**
      * The addition operator, +
@@ -31,13 +31,9 @@ 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;
         }
@@ -53,10 +49,7 @@ public class StandardPlugin extends Plugin {
 
         @Override
         protected NumberInterface applyInternal(NumberInterface[] params) {
-            if(Thread.currentThread().isInterrupted())
-                return null;
             return params[0].subtract(params[1]);
-
         }
     });
     /**
@@ -70,8 +63,6 @@ public class StandardPlugin extends Plugin {
 
         @Override
         protected NumberInterface applyInternal(NumberInterface[] params) {
-            if(Thread.currentThread().isInterrupted())
-                return null;
             return params[0].negate();
         }
     });
@@ -86,13 +77,9 @@ 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;
         }
@@ -103,13 +90,11 @@ public class StandardPlugin extends Plugin {
     public static final Operator OP_DIVIDE = new Operator(OperatorAssociativity.LEFT, OperatorType.BINARY_INFIX, 1, new Function() {
         @Override
         protected boolean matchesParams(NumberInterface[] params) {
-            return params.length == 2;
+            return params.length == 2 && params[1].compareTo(NaiveNumber.ZERO.promoteTo(params[1].getClass())) != 0;
         }
 
         @Override
         protected NumberInterface applyInternal(NumberInterface[] params) {
-            if(Thread.currentThread().isInterrupted())
-                return null;
             return params[0].divide(params[1]);
         }
     });
@@ -120,24 +105,22 @@ public class StandardPlugin extends Plugin {
         //private HashMap<Class<? extends NumberInterface>, ArrayList<NumberInterface>> storedList = new HashMap<Class<? extends NumberInterface>, ArrayList<NumberInterface>>();
         @Override
         protected boolean matchesParams(NumberInterface[] params) {
-            return params.length == 1;
+            return params.length == 1
+                    && params[0].fractionalPart().compareTo(NaiveNumber.ZERO.promoteTo(params[0].getClass())) == 0
+                    && params[0].signum() >= 0;
         }
 
         @Override
         protected NumberInterface applyInternal(NumberInterface[] params) {
-            if(Thread.currentThread().isInterrupted())
-                return null;
             if (params[0].signum() == 0) {
                 return (new NaiveNumber(1)).promoteTo(params[0].getClass());
             }
             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>());
@@ -157,12 +140,7 @@ public class StandardPlugin extends Plugin {
 
         @Override
         protected NumberInterface applyInternal(NumberInterface[] params) {
-            if(Thread.currentThread().isInterrupted())
-                return null;
-            NumberInterface check;
-            if((check = FUNCTION_EXP.apply(FUNCTION_LN.apply(params[0])))!=null&&(check = check.multiply(params[1]))!=null)
-                return check;
-            return null;
+            return FUNCTION_EXP.apply(FUNCTION_LN.apply(params[0]).multiply(params[1]));
         }
     });
     /**
@@ -176,8 +154,6 @@ 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()));
         }
     };
@@ -192,17 +168,14 @@ public class StandardPlugin extends Plugin {
 
         @Override
         protected NumberInterface applyInternal(NumberInterface[] params) {
-            if(Thread.currentThread().isInterrupted())
-                return null;
             NumberInterface maxError = getMaxError(params[0]);
             int n = 0;
             if(params[0].signum() <= 0){
                 NumberInterface currentTerm = NaiveNumber.ONE.promoteTo(params[0].getClass()), sum = currentTerm;
-                NumberInterface check;
-                while((check = FUNCTION_ABS.apply(currentTerm))!=null && (check.compareTo(maxError) > 0)){
+                while(FUNCTION_ABS.apply(currentTerm).compareTo(maxError) > 0){
                     n++;
-                    if(Thread.currentThread().isInterrupted()||(currentTerm = currentTerm.multiply(params[0]))==null||(currentTerm = currentTerm.divide((new NaiveNumber(n)).promoteTo(params[0].getClass())))==null||(sum = (sum.add(currentTerm)))==null)
-                        return null;
+                    currentTerm = currentTerm.multiply(params[0]).divide((new NaiveNumber(n)).promoteTo(params[0].getClass()));
+                    sum = sum.add(currentTerm);
                 }
                 return sum;
             }
@@ -211,28 +184,18 @@ 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())), right = maxError;
-                NumberInterface check;
-                        if((check =intPow(new NaiveNumber(3).promoteTo(params[0].getClass()),params[0].getClass(),(new NaiveNumber(params[0].ceiling())).promoteTo(params[0].getClass())))==null)
-                            return null;
-                        NumberInterface left = params[0].multiply(check), right = maxError;
+                NumberInterface left = params[0].multiply((new NaiveNumber(3)).promoteTo(params[0].getClass()).intPow(params[0].ceiling().intValue())), right = maxError;
                 do{
-                    if((check = factorial(params[0].getClass(),n+1))==null||(check = nextNumerator.divide(check))==null||(sum = sum.add(check))==null)
-                        return null;
+                    sum = sum.add(nextNumerator.divide(factorial(params[0].getClass(), n+1)));
                     n++;
-                    if((nextNumerator = nextNumerator.multiply(params[0]))==null)
-                        return null;
-                    if((left = left.multiply(params[0]))==null)
-                        return null;
+                    nextNumerator = nextNumerator.multiply(params[0]);
+                    left = left.multiply(params[0]);
                     NumberInterface nextN = (new NaiveNumber(n+1)).promoteTo(params[0].getClass());
-                    if((right = right.multiply(nextN))==null)
-                        return null;
+                    right = right.multiply(nextN);
                     //System.out.println(left + ", " + right);
                 }
-                while(!Thread.currentThread().isInterrupted()&&left.compareTo(right) > 0);
+                while(left.compareTo(right) > 0);
                 //System.out.println(n+1);
-               if(Thread.currentThread().isInterrupted())
-                    return null;
                 return sum;
             }
         }
@@ -243,37 +206,31 @@ public class StandardPlugin extends Plugin {
     public static final Function FUNCTION_LN = new Function() {
         @Override
         protected boolean matchesParams(NumberInterface[] params) {
-            return params.length == 1;
+            return params.length == 1 && params[0].compareTo(NaiveNumber.ZERO.promoteTo(params[0].getClass())) > 0;
         }
 
         @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) {
+            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()));
                     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()));
                     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));
         }
 
         /**
@@ -283,23 +240,16 @@ public class StandardPlugin extends Plugin {
          * @return the partial sum.
          */
         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;
         }
 
@@ -309,8 +259,6 @@ 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());
             //We'll use the series \sigma_{n >= 1) ((1/3^n + 1/4^n) * 1/n)
@@ -319,17 +267,13 @@ public class StandardPlugin extends Plugin {
             NumberInterface a = (new NaiveNumber(1)).promoteTo(number.getClass()), 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()));
                 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;
         }
     };
@@ -348,6 +292,160 @@ public class StandardPlugin extends Plugin {
         }
     };
 
+    /**
+     * The sine function (the argument is interpreted in radians).
+     */
+    public final Function functionSin = new Function() {
+        @Override
+        protected boolean matchesParams(NumberInterface[] params) {
+            return params.length == 1;
+        }
+
+        @Override
+        protected NumberInterface applyInternal(NumberInterface[] params) {
+            NumberInterface pi = getPi(params[0].getClass());
+            NumberInterface twoPi = pi.multiply(new NaiveNumber(2).promoteTo(pi.getClass()));
+            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){
+                theta = pi.subtract(theta);
+            }
+            //System.out.println(theta);
+            return sinTaylor(theta);
+        }
+    };
+
+    /**
+     * The cosine function (the argument is in radians).
+     */
+    public final Function functionCos = new Function() {
+        @Override
+        protected boolean matchesParams(NumberInterface[] params) {
+            return params.length == 1;
+        }
+
+        @Override
+        protected NumberInterface applyInternal(NumberInterface[] params) {
+            return functionSin.apply(getPi(params[0].getClass()).divide(new NaiveNumber(2).promoteTo(params[0].getClass()))
+                .subtract(params[0]));
+        }
+    };
+
+    /**
+     * The tangent function (the argument is in radians).
+     */
+    public final Function functionTan = new Function() {
+        @Override
+        protected boolean matchesParams(NumberInterface[] params) {
+            return params.length == 1;
+        }
+
+        @Override
+        protected NumberInterface applyInternal(NumberInterface[] params) {
+            return functionSin.apply(params[0]).divide(functionCos.apply(params[0]));
+        }
+    };
+
+    /**
+     * The secant function (the argument is in radians).
+     */
+    public final Function functionSec = new Function() {
+        @Override
+        protected boolean matchesParams(NumberInterface[] params) {
+            return params.length == 1;
+        }
+
+        @Override
+        protected NumberInterface applyInternal(NumberInterface[] params) {
+            return NaiveNumber.ONE.promoteTo(params[0].getClass()).divide(functionCos.apply(params[0]));
+        }
+    };
+
+    /**
+     * The cosecant function (the argument is in radians).
+     */
+    public final Function functionCsc = new Function() {
+        @Override
+        protected boolean matchesParams(NumberInterface[] params) {
+            return params.length == 1;
+        }
+
+        @Override
+        protected NumberInterface applyInternal(NumberInterface[] params) {
+            return NaiveNumber.ONE.promoteTo(params[0].getClass()).divide(functionSin.apply(params[0]));
+        }
+    };
+
+    /**
+     * The cotangent function (the argument is in radians).
+     */
+    public final Function functionCot = new Function() {
+        @Override
+        protected boolean matchesParams(NumberInterface[] params) {
+            return params.length == 1;
+        }
+
+        @Override
+        protected NumberInterface applyInternal(NumberInterface[] params) {
+            return functionCos.apply(params[0]).divide(functionCos.apply(params[0]));
+        }
+    };
+
+    /**
+     * The implementation for double-based naive numbers.
+     */
+    public static final NumberImplementation IMPLEMENTATION_NAIVE = new NumberImplementation(NaiveNumber.class, 0) {
+        @Override
+        public NumberInterface instanceForString(String string) {
+            return new NaiveNumber(string);
+        }
+
+        @Override
+        public NumberInterface instanceForPi() {
+            return new NaiveNumber(Math.PI);
+        }
+    };
+
+    /**
+     * The implementation for the infinite-precision BigDecimal.
+     */
+    public static final NumberImplementation IMPLEMENTATION_PRECISE = new NumberImplementation(PreciseNumber.class, 0) {
+        @Override
+        public NumberInterface instanceForString(String string) {
+            return new PreciseNumber(string);
+        }
+
+        @Override
+        public NumberInterface instanceForPi() {
+            NumberInterface C = FUNCTION_SQRT.apply(new PreciseNumber("10005")).multiply(new PreciseNumber("426880"));
+            NumberInterface M = PreciseNumber.ONE;
+            NumberInterface L = new PreciseNumber("13591409");
+            NumberInterface X = M;
+            NumberInterface sum = L;
+            int termsNeeded = C.getMaxPrecision()/13 + 1;
+
+            NumberInterface lSummand = new PreciseNumber("545140134");
+            NumberInterface xMultiplier = new PreciseNumber("262537412")
+                    .multiply(new PreciseNumber("1000000000"))
+                    .add(new PreciseNumber("640768000"))
+                    .negate();
+            for(int i = 0; i < termsNeeded; i++){
+                M = M
+                        .multiply(new NaiveNumber(12*i+2).promoteTo(PreciseNumber.class))
+                        .multiply(new NaiveNumber(12*i+6).promoteTo(PreciseNumber.class))
+                        .multiply(new NaiveNumber(12*i+10).promoteTo(PreciseNumber.class))
+                        .divide(new NaiveNumber(Math.pow(i+1,3)).promoteTo(PreciseNumber.class));
+                L = L.add(lSummand);
+                X = X.multiply(xMultiplier);
+                sum = sum.add(M.multiply(L).divide(X));
+            }
+            return C.divide(sum);
+        }
+    };
+
     public StandardPlugin(PluginManager manager) {
         super(manager);
     }
@@ -380,8 +478,8 @@ public class StandardPlugin extends Plugin {
 
     @Override
     public void onEnable() {
-        registerNumber("naive", NaiveNumber.class);
-        registerNumber("precise", PreciseNumber.class);
+        registerNumberImplementation("naive", IMPLEMENTATION_NAIVE);
+        registerNumberImplementation("precise", IMPLEMENTATION_PRECISE);
 
         registerOperator("+", OP_ADD);
         registerOperator("-", OP_SUBTRACT);
@@ -395,6 +493,12 @@ public class StandardPlugin extends Plugin {
         registerFunction("exp", FUNCTION_EXP);
         registerFunction("ln", FUNCTION_LN);
         registerFunction("sqrt", FUNCTION_SQRT);
+        registerFunction("sin", functionSin);
+        registerFunction("cos", functionCos);
+        registerFunction("tan", functionTan);
+        registerFunction("sec", functionSec);
+        registerFunction("csc", functionCsc);
+        registerFunction("cot", functionCot);
     }
 
     @Override
@@ -402,44 +506,58 @@ public class StandardPlugin extends Plugin {
 
     }
 
+    /**
+     * A factorial function that uses memoization for each number class; it efficiently
+     * computes factorials of non-negative integers.
+     * @param numberClass type of number to return.
+     * @param n non-negative integer.
+     * @return a number of numClass with value n factorial.
+     */
     public static NumberInterface factorial(Class<? extends NumberInterface> numberClass, int n){
-        if(Thread.currentThread().isInterrupted())
-            return null;
-        if(!factorialLists.containsKey(numberClass)){
-            factorialLists.put(numberClass, new ArrayList<>());
-            factorialLists.get(numberClass).add(NaiveNumber.ONE.promoteTo(numberClass));
-            factorialLists.get(numberClass).add(NaiveNumber.ONE.promoteTo(numberClass));
+        if(!FACTORIAL_LISTS.containsKey(numberClass)){
+            FACTORIAL_LISTS.put(numberClass, new ArrayList<>());
+            FACTORIAL_LISTS.get(numberClass).add(NaiveNumber.ONE.promoteTo(numberClass));
+            FACTORIAL_LISTS.get(numberClass).add(NaiveNumber.ONE.promoteTo(numberClass));
         }
-        ArrayList<NumberInterface> list = factorialLists.get(numberClass);
+        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);
     }
-    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);
-        }
-        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 (takeReciprocal) {
-            power = (new NaiveNumber(1)).promoteTo(numberClass).divide(power);
-        }
-        if(Thread.currentThread().isInterrupted())
-            return null;
-        return power;
+
+    /**
+     * Returns the value of the Taylor series for sin (centered at 0) at x.
+     * @param x where the series is evaluated.
+     * @return the value of the series
+     */
+    private static NumberInterface sinTaylor(NumberInterface x){
+        NumberInterface power = x, multiplier = x.multiply(x).negate(), currentTerm = x, sum = x;
+        NumberInterface maxError = getMaxError(x);
+        int n = 1;
+        do{
+            n += 2;
+            power = power.multiply(multiplier);
+            currentTerm = power.divide(factorial(x.getClass(), n));
+            sum = sum.add(currentTerm);
+        } while (FUNCTION_ABS.apply(currentTerm).compareTo(maxError) > 0);
+        return sum;
     }
 
+    /**
+     * Returns an equivalent angle in the interval [0, 2pi)
+     * @param phi an angle (in radians).
+     * @return theta in [0, 2pi) that differs from phi by a multiple of 2pi.
+     */
+    private static NumberInterface getSmallAngle(NumberInterface phi, NumberInterface pi){
+        NumberInterface twoPi = pi.multiply(new NaiveNumber("2").promoteTo(phi.getClass()));
+        NumberInterface theta = FUNCTION_ABS.apply(phi).subtract(twoPi
+        .multiply(FUNCTION_ABS.apply(phi).divide(twoPi).floor())); //Now theta is in [0, 2pi).
+        if(phi.signum() < 0){
+            theta = twoPi.subtract(theta);
+        }
+        return theta;
+    }
 }

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

@@ -7,12 +7,13 @@
 <?import javafx.scene.text.Text?>
 <?import javafx.scene.layout.HBox?>
 <?import javafx.scene.layout.GridPane?>
+<?import javafx.scene.layout.FlowPane?>
 <BorderPane xmlns="http://javafx.com/javafx"
             xmlns:fx="http://javafx.com/fxml"
             fx:controller="org.nwapw.abacus.fx.AbacusController">
     <center>
-        <TabPane>
-            <Tab text="Calculator" closable="false">
+        <TabPane fx:id="coreTabPane">
+            <Tab fx:id="calculateTab" text="Calculator" closable="false">
                 <BorderPane>
                     <center>
                         <TableView fx:id="historyTable">
@@ -37,17 +38,23 @@
                             <TextField fx:id="inputField" onAction="#performCalculation"/>
                             <Button fx:id="inputButton" text="Calculate" maxWidth="Infinity"
                                     onAction="#performCalculation"/>
-                            <Button fx:id="stopButton" text="Stop" maxWidth="Infinity"
-                                    onAction="#stopCalculation"/>
                         </VBox>
                     </bottom>
                 </BorderPane>
             </Tab>
-            <Tab text="Settings" closable="false">
+            <Tab fx:id="settingsTab" text="Settings" closable="false">
                 <GridPane hgap="10" vgap="10">
                     <padding><Insets left="10" right="10" top="10" bottom="10"/></padding>
                     <Label text="Number Implementation" GridPane.columnIndex="0" GridPane.rowIndex="0"/>
                     <ComboBox fx:id="numberImplementationBox" GridPane.columnIndex="1" GridPane.rowIndex="0"/>
+                    <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" vgap="10">
+                        <Button text="Apply" onAction="#performSave"/>
+                        <Button text="Reload Plugins" onAction="#performReload"/>
+                        <Button text="Apply and Reload" onAction="#performSaveAndReload"/>
+                    </FlowPane>
                 </GridPane>
             </Tab>
         </TabPane>