Implement the negation operator.

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

@@ -9,7 +9,7 @@ import org.nwapw.abacus.parsing.ShuntingYardParser;
 import org.nwapw.abacus.parsing.TreeBuilder;
 import org.nwapw.abacus.plugin.ClassFinder;
 import org.nwapw.abacus.plugin.PluginManager;
-//import org.nwapw.abacus.plugin.StandardPlugin;
+import org.nwapw.abacus.plugin.StandardPlugin;
 import org.nwapw.abacus.tree.NumberReducer;
 import org.nwapw.abacus.tree.TreeNode;
 
@@ -67,22 +67,16 @@ public class Abacus {
 
         pluginManager.addListener(lexerTokenizer);
         pluginManager.addListener(shuntingYardParser);
-        //pluginManager.addInstantiated(new StandardPlugin(pluginManager));
-        /*
+        pluginManager.addInstantiated(new StandardPlugin(pluginManager));
         try {
             ClassFinder.loadJars("plugins")
                     .forEach(plugin -> pluginManager.addClass(plugin));
         } catch (IOException | ClassNotFoundException e) {
             e.printStackTrace();
-        }//*/
+        }
         pluginManager.load();
     }
-    public void loadClass(Class<?> newClass){
-        pluginManager.addClass(newClass);
-    }
-    public void unloadClass(Class<?> newClass){
-        pluginManager.removeClass(newClass);
-    }
+
     public static void main(String[] args) {
         AbacusApplication.launch(AbacusApplication.class, args);
     }

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

@@ -4,5 +4,5 @@ package org.nwapw.abacus.function;
  * The type of an operator, describing how it should behave.
  */
 public enum OperatorType {
-    BINARY_INFIX, UNARY_POSTFIX
+    BINARY_INFIX, UNARY_POSTFIX, UNARY_PREFIX
 }

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

@@ -8,11 +8,8 @@ import javafx.scene.text.Text;
 import javafx.util.Callback;
 import org.nwapw.abacus.Abacus;
 import org.nwapw.abacus.number.NumberInterface;
-import org.nwapw.abacus.plugin.ClassFinder;
 import org.nwapw.abacus.tree.TreeNode;
 
-import java.io.IOException;
-
 
 /**
  * The controller for the abacus FX UI, responsible
@@ -45,12 +42,6 @@ public class AbacusController {
     private Button inputButton;
     @FXML
     private ComboBox<String> numberImplementationBox;
-    @FXML
-    private Button loadButton;
-    @FXML
-    private Button unloadButton;
-    @FXML
-    private TextField loadField;
 
     /**
      * The list of history entries, created by the users.
@@ -115,38 +106,5 @@ public class AbacusController {
         inputButton.setDisable(false);
         inputField.setText("");
     }
-    @FXML
-    private void loadClass(){
-        try {
-            for(Class<?> plugin :ClassFinder.loadJars("plugins")){
-                String name = "";
-                //String name = plugin.getName();
-                while(!(name.indexOf('/') ==-1)){
-                    name=name.substring(name.indexOf('/')+1);
-                }
-                if(loadField.getText().equals("")||loadField.getText().equals(name)||(loadField.getText()+".class").equals(name)){
-                    //abacus.loadClass(plugin);
-                }
-            }
-        } catch (IOException | ClassNotFoundException e) {
-            e.printStackTrace();
-        }
-    }
-    @FXML
-    private void unloadClass(){
-        try {
-            for(Class<?> plugin :ClassFinder.loadJars("plugins")){
-                String name = plugin.getName();
-                while(!(name.indexOf('/') ==-1)){
-                    name=name.substring(name.indexOf('/')+1);
-                }
-                if(loadField.getText().equals("")||loadField.getText().equals(name)||(loadField.getText()+".class").equals(name)){
-                    //abacus.unloadClass(plugin);
-                }
-            }
-        } catch (IOException | ClassNotFoundException e) {
-            e.printStackTrace();
-        }
-    }
 
 }

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

@@ -55,9 +55,12 @@ public class ShuntingYardParser implements Parser<Match<TokenType>>, PluginListe
     public List<Match<TokenType>> intoPostfix(List<Match<TokenType>> from) {
         ArrayList<Match<TokenType>> output = new ArrayList<>();
         Stack<Match<TokenType>> tokenStack = new Stack<>();
+        TokenType previousType;
+        TokenType matchType = null;
         while (!from.isEmpty()) {
             Match<TokenType> match = from.remove(0);
-            TokenType matchType = match.getType();
+            previousType = matchType;
+            matchType = match.getType();
             if (matchType == TokenType.NUM) {
                 output.add(match);
             } else if (matchType == TokenType.FUNCTION) {
@@ -74,7 +77,13 @@ public class ShuntingYardParser implements Parser<Match<TokenType>>, PluginListe
                     continue;
                 }
 
-                while (!tokenStack.empty()) {
+                if(tokenString.equals("-") && (previousType == null || previousType == TokenType.OP ||
+                        previousType == TokenType.OPEN_PARENTH)){
+                    from.add(0, new Match<>("`", TokenType.OP));
+                    continue;
+                }
+
+                while (!tokenStack.empty() && type == OperatorType.BINARY_INFIX) {
                     Match<TokenType> otherMatch = tokenStack.peek();
                     TokenType otherMatchType = otherMatch.getType();
                     if (!(otherMatchType == TokenType.OP || otherMatchType == TokenType.FUNCTION)) break;
@@ -103,8 +112,8 @@ public class ShuntingYardParser implements Parser<Match<TokenType>>, PluginListe
         }
         while (!tokenStack.empty()) {
             Match<TokenType> match = tokenStack.peek();
-            TokenType matchType = match.getType();
-            if (!(matchType == TokenType.OP || matchType == TokenType.FUNCTION)) return null;
+            TokenType newMatchType = match.getType();
+            if (!(newMatchType == TokenType.OP || newMatchType == TokenType.FUNCTION)) return null;
             output.add(tokenStack.pop());
         }
         return output;
@@ -127,11 +136,11 @@ public class ShuntingYardParser implements Parser<Match<TokenType>>, PluginListe
                 TreeNode right = constructRecursive(matches);
                 TreeNode left = constructRecursive(matches);
                 if (left == null || right == null) return null;
-                else return new BinaryInfixNode(operator, left, right);
+                else return new BinaryNode(operator, left, right);
             } else {
                 TreeNode applyTo = constructRecursive(matches);
                 if (applyTo == null) return null;
-                else return new UnaryPrefixNode(operator, applyTo);
+                else return new UnaryNode(operator, applyTo);
             }
         } else if (matchType == TokenType.NUM) {
             return new NumberNode(abacus.numberFromString(match.getContent()));

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

@@ -140,11 +140,6 @@ public class PluginManager {
         plugins.add(plugin);
         loadedPluginClasses.add(plugin.getClass());
     }
-    public void removeInstantiated(Plugin plugin){
-        if (loadedPluginClasses.contains(plugin.getClass())) return;
-        plugins.remove(plugin);
-        loadedPluginClasses.remove(plugin.getClass());
-    }
 
     /**
      * Instantiates a class of plugin, and adds it to this
@@ -160,14 +155,6 @@ public class PluginManager {
             e.printStackTrace();
         }
     }
-    public void removeClass(Class<?> newClass){
-        if (!Plugin.class.isAssignableFrom(newClass) || newClass == Plugin.class) return;
-        try {
-            removeInstantiated((Plugin) newClass.getConstructor(PluginManager.class).newInstance(this));
-        } catch (InstantiationException | IllegalAccessException | NoSuchMethodException | InvocationTargetException e) {
-            e.printStackTrace();
-        }
-    }
 
     /**
      * Loads all the plugins in the PluginManager.

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

@@ -52,6 +52,20 @@ public class StandardPlugin extends Plugin {
             return params[0].subtract(params[1]);
         }
     });
+    /**
+     * The negation operator, -
+     */
+    public static final Operator OP_NEGATE = new Operator(OperatorAssociativity.LEFT, OperatorType.UNARY_PREFIX, 0, new Function() {
+        @Override
+        protected boolean matchesParams(NumberInterface[] params) {
+            return params.length == 1;
+        }
+
+        @Override
+        protected NumberInterface applyInternal(NumberInterface[] params) {
+            return params[0].negate();
+        }
+    });
     /**
      * The multiplication operator, *
      */
@@ -317,6 +331,7 @@ public class StandardPlugin extends Plugin {
 
         registerOperator("+", OP_ADD);
         registerOperator("-", OP_SUBTRACT);
+        registerOperator("`", OP_NEGATE);
         registerOperator("*", OP_MULTIPLY);
         registerOperator("/", OP_DIVIDE);
         registerOperator("^", OP_CARET);
@@ -335,7 +350,7 @@ public class StandardPlugin extends Plugin {
 
     public static NumberInterface factorial(Class<? extends NumberInterface> numberClass, int n){
         if(!factorialLists.containsKey(numberClass)){
-            factorialLists.put(numberClass, new ArrayList<NumberInterface>());
+            factorialLists.put(numberClass, new ArrayList<>());
             factorialLists.get(numberClass).add(NaiveNumber.ONE.promoteTo(numberClass));
             factorialLists.get(numberClass).add(NaiveNumber.ONE.promoteTo(numberClass));
         }

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

@@ -3,7 +3,7 @@ package org.nwapw.abacus.tree;
 /**
  * A tree node that represents an operation being applied to two operands.
  */
-public class BinaryInfixNode extends TreeNode {
+public class BinaryNode extends TreeNode {
 
     /**
      * The operation being applied.
@@ -18,7 +18,7 @@ public class BinaryInfixNode extends TreeNode {
      */
     private TreeNode right;
 
-    private BinaryInfixNode() {
+    private BinaryNode() {
     }
 
     /**
@@ -27,7 +27,7 @@ public class BinaryInfixNode extends TreeNode {
      *
      * @param operation the operation.
      */
-    public BinaryInfixNode(String operation) {
+    public BinaryNode(String operation) {
         this(operation, null, null);
     }
 
@@ -39,7 +39,7 @@ public class BinaryInfixNode extends TreeNode {
      * @param left      the left node of the expression.
      * @param right     the right node of the expression.
      */
-    public BinaryInfixNode(String operation, TreeNode left, TreeNode right) {
+    public BinaryNode(String operation, TreeNode left, TreeNode right) {
         this.operation = operation;
         this.left = left;
         this.right = right;

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

@@ -28,15 +28,15 @@ public class NumberReducer implements Reducer<NumberInterface> {
     public NumberInterface reduceNode(TreeNode node, Object... children) {
         if (node instanceof NumberNode) {
             return ((NumberNode) node).getNumber();
-        } else if (node instanceof BinaryInfixNode) {
+        } else if (node instanceof BinaryNode) {
             NumberInterface left = (NumberInterface) children[0];
             NumberInterface right = (NumberInterface) children[1];
-            Function function = abacus.getPluginManager().operatorFor(((BinaryInfixNode) node).getOperation()).getFunction();
+            Function function = abacus.getPluginManager().operatorFor(((BinaryNode) node).getOperation()).getFunction();
             if (function == null) return null;
             return function.apply(left, right);
-        } else if (node instanceof UnaryPrefixNode) {
+        } else if (node instanceof UnaryNode) {
             NumberInterface child = (NumberInterface) children[0];
-            Function functionn = abacus.getPluginManager().operatorFor(((UnaryPrefixNode) node).getOperation()).getFunction();
+            Function functionn = abacus.getPluginManager().operatorFor(((UnaryNode) node).getOperation()).getFunction();
             if (functionn == null) return null;
             return functionn.apply(child);
         } else if (node instanceof FunctionNode) {

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

@@ -1,6 +1,6 @@
 package org.nwapw.abacus.tree;
 
-public class UnaryPrefixNode extends TreeNode {
+public class UnaryNode extends TreeNode {
 
     /**
      * The operation this node will apply.
@@ -16,7 +16,7 @@ public class UnaryPrefixNode extends TreeNode {
      *
      * @param operation the operation for this node.
      */
-    public UnaryPrefixNode(String operation) {
+    public UnaryNode(String operation) {
         this(operation, null);
     }
 
@@ -26,7 +26,7 @@ public class UnaryPrefixNode extends TreeNode {
      * @param operation the operation for this node.
      * @param applyTo   the node to apply the function to.
      */
-    public UnaryPrefixNode(String operation, TreeNode applyTo) {
+    public UnaryNode(String operation, TreeNode applyTo) {
         this.operation = operation;
         this.applyTo = applyTo;
     }

src/main/resources/abacus.fxml

@@ -46,9 +46,6 @@
                     <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"/>
-                    <Button fx:id="loadButton" text="Load" GridPane.rowIndex="1" GridPane.columnIndex="0" maxWidth = "Infinity" onAction="#loadClass"/>
-                    <Button fx:id="unloadButton" text="Unload" GridPane.rowIndex="1" GridPane.columnIndex="1" maxWidth = "Infinity" onAction="#unloadClass"/>
-                    <TextField fx:id="loadField" GridPane.rowIndex="1" GridPane.columnIndex="2"/>
                 </GridPane>
             </Tab>
         </TabPane>