Implement unary operators.

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

@@ -30,6 +30,7 @@ public class Operator {
      */
     public Operator(OperatorAssociativity associativity, OperatorType operatorType, int precedence, Function function){
         this.associativity = associativity;
+        this.type = operatorType;
         this.precedence = precedence;
         this.function = function;
     }

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

@@ -89,7 +89,7 @@ public class StandardPlugin extends Plugin {
             }
         }));
 
-        registerFunction("!", new Function() {
+        registerOperator("!", new Operator(OperatorAssociativity.RIGHT, OperatorType.UNARY_POSTFIX, 0, new Function() {
             //private HashMap<Class<? extends NumberInterface>, ArrayList<NumberInterface>> storedList = new HashMap<Class<? extends NumberInterface>, ArrayList<NumberInterface>>();
             @Override
             protected boolean matchesParams(NumberInterface[] params) {
@@ -114,7 +114,7 @@ public class StandardPlugin extends Plugin {
                     storedList.get(params[0].getClass()).add(NaiveNumber.ONE.promoteTo(params[0].getClass()));
                 }*/
             }
-        });
+        }));
 
         registerFunction("abs", new Function() {
             @Override

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

@@ -33,6 +33,11 @@ public class NumberReducer implements Reducer<NumberInterface> {
             Function function = manager.operatorFor(((OpNode) node).getOperation()).getFunction();
             if(function == null) return null;
             return function.apply(left, right);
+        } else if(node instanceof UnaryPrefixNode) {
+            NumberInterface child = (NumberInterface) children[0];
+            Function functionn = manager.operatorFor(((UnaryPrefixNode) node).getOperation()).getFunction();
+            if(functionn == null) return null;
+            return functionn.apply(child);
         } else if(node instanceof FunctionNode){
             NumberInterface[] convertedChildren = new NumberInterface[children.length];
             for(int i = 0; i < convertedChildren.length; i++){

src/org/nwapw/abacus/tree/TreeBuilder.java

@@ -101,9 +101,15 @@ public class TreeBuilder {
                 tokenStack.push(match);
             } else if(matchType == TokenType.OP){
                 String tokenString = source.substring(match.getFrom(), match.getTo());
+                OperatorType type = typeMap.get(tokenString);
                 int precedence = precedenceMap.get(tokenString);
                 OperatorAssociativity associativity = associativityMap.get(tokenString);
 
+                if(type == OperatorType.UNARY_POSTFIX){
+                    output.add(match);
+                    continue;
+                }
+
                 while(!tokenStack.empty()) {
                     Match<TokenType> otherMatch = tokenStack.peek();
                     TokenType otherMatchType = otherMatch.getType();
@@ -151,10 +157,18 @@ public class TreeBuilder {
         Match<TokenType> match = matches.remove(0);
         TokenType matchType = match.getType();
         if(matchType == TokenType.OP){
+            String operator = source.substring(match.getFrom(), match.getTo());
+            OperatorType type = typeMap.get(operator);
+            if(type == OperatorType.BINARY_INFIX){
                 TreeNode right = fromStringRecursive(source, matches);
                 TreeNode left = fromStringRecursive(source, matches);
                 if(left == null || right == null) return null;
-            else return new OpNode(source.substring(match.getFrom(), match.getTo()), left, right);
+                else return new OpNode(operator, left, right);
+            } else {
+                TreeNode applyTo = fromStringRecursive(source, matches);
+                if(applyTo == null) return null;
+                else return new UnaryPrefixNode(operator, applyTo);
+            }
         } else if(matchType == TokenType.NUM){
             return new NumberNode(Double.parseDouble(source.substring(match.getFrom(), match.getTo())));
         } else if(matchType == TokenType.FUNCTION){

src/org/nwapw/abacus/tree/UnaryPrefixNode.java

@@ -0,0 +1,54 @@
+package org.nwapw.abacus.tree;
+
+public class UnaryPrefixNode extends TreeNode {
+
+    /**
+     * The operation this node will apply.
+     */
+    private String operation;
+    /**
+     * The tree node to apply the operation to.
+     */
+    private TreeNode applyTo;
+
+    /**
+     * Creates a new node with the given operation and no child.
+     * @param operation the operation for this node.
+     */
+    public UnaryPrefixNode(String operation){
+        this(operation, null);
+    }
+
+    /**
+     * Creates a new node with the given operation and child.
+     * @param operation the operation for this node.
+     * @param applyTo the node to apply the function to.
+     */
+    public UnaryPrefixNode(String operation, TreeNode applyTo){
+        this.operation = operation;
+        this.applyTo = applyTo;
+    }
+
+    @Override
+    public <T> T reduce(Reducer<T> reducer) {
+        Object reducedChild = applyTo.reduce(reducer);
+        if(reducedChild == null) return null;
+        return reducer.reduceNode(this, reducedChild);
+    }
+
+    /**
+     * Gets the operation of this node.
+     * @return the operation this node performs.
+     */
+    public String getOperation() {
+        return operation;
+    }
+
+    /**
+     * Gets the node to which this node's operation applies.
+     * @return the tree node to which the operation will be applied.
+     */
+    public TreeNode getApplyTo() {
+        return applyTo;
+    }
+}