Moved temporary variable creation from Parser to Expression.

src/main/java/com/sk89q/worldedit/EditSession.java

@@ -2635,8 +2635,8 @@ public class EditSession {
         final Expression expression = Expression.compile(expressionString, "x", "y", "z", "type", "data");
         expression.optimize();
 
-        final RValue typeVariable = expression.getVariable("type");
+        final RValue typeVariable = expression.getVariable("type", false);
-        final RValue dataVariable = expression.getVariable("data");
+        final RValue dataVariable = expression.getVariable("data", false);
 
         final ArbitraryShape shape = new ArbitraryShape(region) {
             @Override
@@ -2663,9 +2663,9 @@ public class EditSession {
         final Expression expression = Expression.compile(expressionString, "x", "y", "z");
         expression.optimize();
 
-        final RValue x = expression.getVariable("x");
+        final RValue x = expression.getVariable("x", false);
-        final RValue y = expression.getVariable("y");
+        final RValue y = expression.getVariable("y", false);
-        final RValue z = expression.getVariable("z");
+        final RValue z = expression.getVariable("z", false);
 
         Vector zero2 = zero.add(0.5, 0.5, 0.5);
 

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

@@ -84,7 +84,7 @@ public class Expression {
             variables.put(variableName, new Variable(0));
         }
 
-        root = Parser.parse(tokens, variables);
+        root = Parser.parse(tokens, this);
     }
 
     public double evaluate(double... values) throws EvaluationException {
@@ -114,7 +114,12 @@ public class Expression {
         return root.toString();
     }
 
-    public RValue getVariable(String name) {
+    public RValue getVariable(String name, boolean create) {
-        return variables.get(name);
+        RValue variable = variables.get(name);
+        if (variable == null && create) {
+            variables.put(name, variable = new Variable(0));
+        }
+
+        return variable;
     }
 }

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

@@ -22,8 +22,7 @@ package com.sk89q.worldedit.expression.parser;
 import java.util.ArrayList;
 import java.util.LinkedList;
 import java.util.List;
-import java.util.Map;
+import com.sk89q.worldedit.expression.Expression;
-
 import com.sk89q.worldedit.expression.Identifiable;
 import com.sk89q.worldedit.expression.lexer.tokens.IdentifierToken;
 import com.sk89q.worldedit.expression.lexer.tokens.KeywordToken;
@@ -40,7 +39,6 @@ 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.SimpleFor;
-import com.sk89q.worldedit.expression.runtime.Variable;
 import com.sk89q.worldedit.expression.runtime.While;
 
 /**
@@ -68,15 +66,15 @@ public class Parser {
 
     private final List<Token> tokens;
     private int position = 0;
-    private Map<String, RValue> variables;
+    private Expression expression;
 
-    private Parser(List<Token> tokens, Map<String, RValue> variables) {
+    private Parser(List<Token> tokens, Expression expression) {
         this.tokens = tokens;
-        this.variables = variables;
+        this.expression = expression;
     }
 
-    public static final RValue parse(List<Token> tokens, Map<String, RValue> variables) throws ParserException {
+    public static final RValue parse(List<Token> tokens, Expression expression) throws ParserException {
-        return new Parser(tokens, variables).parse();
+        return new Parser(tokens, expression).parse();
     }
 
     private RValue parse() throws ParserException {
@@ -176,9 +174,7 @@ public class Parser {
                             throw new ParserException(variableToken.getPosition(), "Expected identifier");
                         }
 
-                        // In theory, I should have to create non-existant variables here.
+                        RValue variable = expression.getVariable(((IdentifierToken) variableToken).value, true);
-                        // However, the java-for parsing attempt further up already takes care of that :) 
-                        RValue variable = variables.get(((IdentifierToken) variableToken).value);
                         if (!(variable instanceof LValue)) {
                             throw new ParserException(variableToken.getPosition(), "Expected variable");
                         }
@@ -286,14 +282,11 @@ public class Parser {
                 if (next.id() == '(') {
                     halfProcessed.add(parseFunctionCall(identifierToken));
                 } else {
-                    RValue variable = variables.get(identifierToken.value);
+                    // Ugly hack to make temporary variables work while not sacrificing error reporting.
+                    final boolean isSimpleAssignment = next instanceof OperatorToken && ((OperatorToken) next).operator.equals("=");
+                    RValue variable = expression.getVariable(identifierToken.value, isSimpleAssignment);
                     if (variable == null) {
-                        if (next instanceof OperatorToken && ((OperatorToken) next).operator.equals("=")) {
+                        throw new ParserException(current.getPosition(), "Variable '" + identifierToken.value + "' not found");
-                            // Ugly hack to make temporary variables work while not sacrificing error reporting.
-                            variables.put(identifierToken.value, variable = new Variable(0));
-                        } else {
-                            throw new ParserException(current.getPosition(), "Variable '" + identifierToken.value + "' not found");
-                        }
                     }
                     halfProcessed.add(variable);
                 }

src/test/java/com/sk89q/worldedit/expression/ExpressionTest.java

@@ -65,9 +65,9 @@ public class ExpressionTest {
     public void testAssign() throws ExpressionException {
         Expression foo = compile("{a=x} b=y; c=z", "x", "y", "z", "a", "b", "c");
         foo.evaluate(2, 3, 5);
-        assertEquals(2, foo.getVariable("a").getValue(), 0);
+        assertEquals(2, foo.getVariable("a", false).getValue(), 0);
-        assertEquals(3, foo.getVariable("b").getValue(), 0);
+        assertEquals(3, foo.getVariable("b", false).getValue(), 0);
-        assertEquals(5, foo.getVariable("c").getValue(), 0);
+        assertEquals(5, foo.getVariable("c", false).getValue(), 0);
     }
 
     @Test
@@ -78,13 +78,13 @@ public class ExpressionTest {
         // test 'dangling else'
         final Expression expression1 = compile("if (1) if (0) x=4; else y=5;", "x", "y");
         expression1.evaluate(1, 2);
-        assertEquals(1, expression1.getVariable("x").getValue(), 0);
+        assertEquals(1, expression1.getVariable("x", false).getValue(), 0);
-        assertEquals(5, expression1.getVariable("y").getValue(), 0);
+        assertEquals(5, expression1.getVariable("y", false).getValue(), 0);
 
         // test if the if construct is correctly recognized as a statement
         final Expression expression2 = compile("if (0) if (1) x=5; y=4;", "x", "y");
         expression2.evaluate(1, 2);
-        assertEquals(4, expression2.getVariable("y").getValue(), 0);
+        assertEquals(4, expression2.getVariable("y", false).getValue(), 0);
     }
 
     @Test