Added return, break and continue.

src/main/java/com/sk89q/worldedit/expression/Expression.java

@@ -29,6 +29,7 @@ import com.sk89q.worldedit.expression.parser.Parser;
 import com.sk89q.worldedit.expression.runtime.Constant;
 import com.sk89q.worldedit.expression.runtime.EvaluationException;
 import com.sk89q.worldedit.expression.runtime.RValue;
+import com.sk89q.worldedit.expression.runtime.ReturnException;
 import com.sk89q.worldedit.expression.runtime.Variable;
 
 /**
@@ -97,7 +98,12 @@ public class Expression {
             ((Variable) invokable).value = values[i];
         }
 
-        return root.getValue();
+        try {
+            return root.getValue();
+        }
+        catch (ReturnException e) {
+            return e.getValue();
+        }
     }
 
     public void optimize() throws EvaluationException {

src/main/java/com/sk89q/worldedit/expression/Identifiable.java

@@ -48,6 +48,8 @@ public interface Identifiable {
      * I - Conditional
      * w - While
      * F - For
+     * r - Return
+     * b - Break (includes continue)
      * </pre>
      */
     public abstract char id();

src/main/java/com/sk89q/worldedit/expression/lexer/Lexer.java

@@ -107,7 +107,7 @@ public class Lexer {
         characterTokens.add(';');
     }
 
-    private static final Set<String> keywords = new HashSet<String>(Arrays.asList("if", "else", "while", "do", "for"));
+    private static final Set<String> keywords = new HashSet<String>(Arrays.asList("if", "else", "while", "do", "for", "break", "continue", "return"));
 
     private static final Pattern numberPattern = Pattern.compile("^([0-9]*(?:\\.[0-9]+)?(?:[eE][+-]?[0-9]+)?)");
     private static final Pattern identifierPattern = Pattern.compile("^([A-Za-z][0-9A-Za-z_]*)");

src/main/java/com/sk89q/worldedit/expression/parser/Parser.java

@@ -30,11 +30,13 @@ import com.sk89q.worldedit.expression.lexer.tokens.KeywordToken;
 import com.sk89q.worldedit.expression.lexer.tokens.NumberToken;
 import com.sk89q.worldedit.expression.lexer.tokens.OperatorToken;
 import com.sk89q.worldedit.expression.lexer.tokens.Token;
+import com.sk89q.worldedit.expression.runtime.Break;
 import com.sk89q.worldedit.expression.runtime.Conditional;
 import com.sk89q.worldedit.expression.runtime.Constant;
 import com.sk89q.worldedit.expression.runtime.For;
 import com.sk89q.worldedit.expression.runtime.Functions;
 import com.sk89q.worldedit.expression.runtime.RValue;
+import com.sk89q.worldedit.expression.runtime.Return;
 import com.sk89q.worldedit.expression.runtime.Sequence;
 import com.sk89q.worldedit.expression.runtime.Variable;
 import com.sk89q.worldedit.expression.runtime.While;
@@ -163,6 +165,28 @@ public class Parser {
                     break;
                 }
 
+                case 'b': // break
+                    ++position;
+                    statements.add(new Break(current.getPosition(), false));
+                    break;
+
+                case 'c': // continue
+                    ++position;
+                    statements.add(new Break(current.getPosition(), true));
+                    break;
+
+                case 'r': // return
+                    ++position;
+                    statements.add(new Return(current.getPosition(), parseExpression(true)));
+
+                    if (peek().id() == ';') {
+                        ++position;
+                        break;
+                    }
+                    else {
+                        break loop;
+                    }
+
                 default:
                     throw new ParserException(current.getPosition(), "Unimplemented keyword '" + keyword + "'");
                 }

src/main/java/com/sk89q/worldedit/expression/runtime/Break.java

@@ -0,0 +1,28 @@
+package com.sk89q.worldedit.expression.runtime;
+
+public class Break extends Node {
+    boolean doContinue;
+
+    public Break(int position, boolean doContinue) {
+        super(position);
+
+        this.doContinue = doContinue;
+    }
+
+    @Override
+    public double getValue() throws EvaluationException {
+        throw new BreakException(doContinue);
+    }
+
+    @Override
+    public char id() {
+        return 'b';
+    }
+
+    @Override
+    public String toString() {
+        return doContinue ? "continue" : "break";
+    }
+
+    //TODO: optimizer
+}

src/main/java/com/sk89q/worldedit/expression/runtime/BreakException.java

@@ -0,0 +1,13 @@
+package com.sk89q.worldedit.expression.runtime;
+
+public class BreakException extends EvaluationException {
+    private static final long serialVersionUID = 1L;
+
+    final boolean doContinue;
+
+    public BreakException(boolean doContinue) {
+        super(-1, doContinue ? "'continue' encountered outside a loop" : "'break' encountered outside a loop");
+
+        this.doContinue = doContinue;
+    }
+}

src/main/java/com/sk89q/worldedit/expression/runtime/For.java

@@ -21,11 +21,21 @@ public class For extends Node {
         double ret = 0.0;
 
         for (init.getValue(); condition.getValue() > 0; increment.getValue()) {
-            ret = body.getValue();
-            ++iterations;
             if (iterations > 256) {
                 throw new EvaluationException(getPosition(), "Loop exceeded 256 iterations.");
             }
+            ++iterations;
+
+            try {
+                ret = body.getValue();
+            }
+            catch (BreakException e) {
+                if (e.doContinue) {
+                    continue;
+                } else {
+                    break;
+                }
+            }
         }
 
         return ret;

src/main/java/com/sk89q/worldedit/expression/runtime/Return.java

@@ -0,0 +1,28 @@
+package com.sk89q.worldedit.expression.runtime;
+
+public class Return extends Node {
+    RValue value;
+
+    public Return(int position, RValue value) {
+        super(position);
+
+        this.value = value;
+    }
+
+    @Override
+    public double getValue() throws EvaluationException {
+        throw new ReturnException(value.getValue());
+    }
+
+    @Override
+    public char id() {
+        return 'r';
+    }
+
+    @Override
+    public String toString() {
+        return "return "+value;
+    }
+
+    //TODO: optimizer
+}

src/main/java/com/sk89q/worldedit/expression/runtime/ReturnException.java

@@ -0,0 +1,17 @@
+package com.sk89q.worldedit.expression.runtime;
+
+public class ReturnException extends EvaluationException {
+    private static final long serialVersionUID = 1L;
+
+    final double value;
+
+    public ReturnException(double value) {
+        super(-1);
+
+        this.value = value;
+    }
+
+    public double getValue() {
+        return value;
+    }
+}

src/main/java/com/sk89q/worldedit/expression/runtime/While.java

@@ -20,19 +20,39 @@ public class While extends Node {
 
         if (footChecked) {
             do {
-                ret = body.getValue();
-                ++iterations;
                 if (iterations > 256) {
                     throw new EvaluationException(getPosition(), "Loop exceeded 256 iterations.");
                 }
+                ++iterations;
+
+                try {
+                    ret = body.getValue();
+                }
+                catch (BreakException e) {
+                    if (e.doContinue) {
+                        continue;
+                    } else {
+                        break;
+                    }
+                }
             } while (condition.getValue() > 0.0);
         } else {
             while (condition.getValue() > 0.0) {
-                ret = body.getValue();
-                ++iterations;
                 if (iterations > 256) {
                     throw new EvaluationException(getPosition(), "Loop exceeded 256 iterations.");
                 }
+                ++iterations;
+
+                try {
+                    ret = body.getValue();
+                }
+                catch (BreakException e) {
+                    if (e.doContinue) {
+                        continue;
+                    } else {
+                        break;
+                    }
+                }
             }
         }