Refactor constant part.

frog/leg/compile_time_constants.dart

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 class Constant implements Hashable {
   const Constant();
 
   bool isNull() => false;
   /** [isInt] implies [isNum]. */
   bool isInt() => false;
   /** [isDouble] implies [isNum]. */
   bool isDouble() => false;
   bool isBool() => false;
   bool isString() => false;
   /** [isList] implies [isObject]. */
   bool isList() => false;
   /** [isMap] implies [isObject]. */
   bool isMap() => false;
   bool isConstructedObject() => false;
 
   bool isNum() => isInt() || isDouble();
   bool isObject() => isList() || isMap() || isConstructedObject();
+  bool isTrue() {

[kasperl, 2012/03/05 13:53:16]

This smells like you should have two separate BoolConstants: TrueConstant and
FalseConstant.

[floitsch, 2012/03/05 15:43:24]

I will do that when I introduce caching for the common constants.

+    if (!isBool()) return false;
+    BoolConstant boolConstant = this;
+    return boolConstant.value;
+  }
+  bool isFalse() {
+    if (!isBool()) return false;
+    BoolConstant boolConstant = this;
+    return !boolConstant.value;
+  }
 
   /**
    * Returns [:null:] if the operation is not supported on this constant.
    * The [op] operator is assumed to be a prefix operator.
    */
   Constant unaryFold(String op) => null;
 
   /**
    * Returns [:null:] if the operation is not supported on this constant, or
    * if the operation would have thrown an exception.
    */
   Constant binaryFold(String op, Constant other) {

[kasperl, 2012/03/05 13:53:16]

It sort of rubs me the wrong way to use a string for the operation here.

[floitsch, 2012/03/05 15:43:24]

will fix in another CL.

     if (op == "==" || op == "===") {
       return new BoolConstant(this == other);
     } else if (op == "!=" || op == "!==") {
       return new BoolConstant(this != other);
     }
   }
 
   abstract void writeJsCode(StringBuffer buffer,
                             CompileTimeConstantHandler handler);
 }
 
 class PrimitiveConstant extends Constant {
   // TODO(floitsch): this should be an abstract getter, but there is a bug in
   // the VM.

[kasperl, 2012/03/05 13:53:16]

Did you file this as a bug? Update comment with bug number.

[floitsch, 2012/03/05 15:43:24]

bug is gone.

   get value() => null;
   const PrimitiveConstant();
 
   bool operator ==(var other) {
     if (other is !PrimitiveConstant) return false;
     PrimitiveConstant otherPrimitive = other;
     // We use == instead of === so that DartStrings compare correctly. 
     return value == otherPrimitive.value;
   }
+
+  String toString() => value.toString();
 }
 
 class NullConstant extends PrimitiveConstant {
   const NullConstant();
   bool isNull() => true;
   get value() => null;
 
   void writeJsCode(StringBuffer buffer, CompileTimeConstantHandler handler) {
     buffer.add("(void 0)");
   }
@@ skipping 39 matching lines @@
           case "-": return new IntConstant(value - right);
           case "*": return new IntConstant(value * right);
           case "%": return new IntConstant(value % right);
           case "~/": return new IntConstant(value ~/ right);
           case "|": return new IntConstant(value | right);
           case "&": return new IntConstant(value & right);
           case "^": return new IntConstant(value ^ right);        
           case "<<":
             // TODO(floitsch): find a better way to guard against shifts to the
             // left.
-            if (right > 100) null;
-            if (right < 0) null;
+            if (right > 100) return null;
+            if (right < 0) return null;
             return new IntConstant(value << right);
           case ">>":
             if (right < 0) return null;
             return new IntConstant(value >> right);
         }
       } else if (other.isDouble()) {
         double right = rightNum;
         switch (op) {
           case "+": return new DoubleConstant(value + right);
           case "-": return new DoubleConstant(value - right);
@@ skipping 160 matching lines @@
     // TODO(floitsch): create a better hash. 
     int hash = 0;
     for (Constant input in entries) hash ^= input.hashCode();
     _hashCode = hash;
   }
   bool isList() => true;
 
   void writeJsCode(StringBuffer buffer, CompileTimeConstantHandler handler) {
     // TODO(floitsch): we should not need to go through the compiler to make
     // the list constant.
-    buffer.add(handler.compiler.namer.ISOLATE);
-    buffer.add(".prototype.makeConstantList");
+    String isolatePrototype = "${handler.compiler.namer.ISOLATE}.prototype";
+    buffer.add("$isolatePrototype.makeConstantList");
     buffer.add("([");
     for (int i = 0; i < entries.length; i++) {
       if (i != 0) buffer.add(", ");
       Constant entry = entries[i];
       if (entry.isObject()) {
-        handler.getNameForConstant(entry);
+        String name = handler.getNameForConstant(entry);
+        buffer.add("$isolatePrototype.$name");
       } else {
         entry.writeJsCode(buffer, handler);
       }
     }
     buffer.add("])");
   }
 
   bool operator ==(var other) {
     if (other is !ListConstant) return false;
     ListConstant otherList = other;
@@ skipping 94 matching lines @@
            || work.element.kind == ElementKind.PARAMETER);
     VariableElement element = work.element;
     // Shortcut if it has already been compiled.
     if (initialVariableValues.containsKey(element)) return;
     compileVariableWithDefinitions(element, work.resolutionTree);
   }
 
   compileVariable(VariableElement element) {
     if (initialVariableValues.containsKey(element)) {
       Constant result = initialVariableValues[element];
-      // TODO(floitsch): remove the following line once the rest of the
-      // compiler has been adapted.
-      if (!result.isObject()) return result.dynamic.value;
       return result;
     }
     // TODO(floitsch): keep track of currently compiling elements so that we
     // don't end up in an infinite loop: final x = y; final y = x;
     TreeElements definitions = compiler.analyzeElement(element);
     Constant constant =  compileVariableWithDefinitions(element, definitions);
-    // TODO(floitsch): remove the following line once the rest of the
-    // compiler has been adapted.
-    if (!constant.isObject()) return constant.dynamic.value;
     return constant;
   }
 
   compileVariableWithDefinitions(VariableElement element,
                                  TreeElements definitions) {
     return measure(() {
       Node node = element.parseNode(compiler);
       assert(node !== null);
       SendSet assignment = node.asSendSet();
       var value;
@@ skipping 220 matching lines @@
   }
 
   // TODO(floitsch): provide better error-messages.
   visitSend(Send send) {
     Element element = definitions[send];
     if (Elements.isStaticOrTopLevelField(element)) {
       if (element.modifiers === null ||
           !element.modifiers.isFinal()) {
         error(send);
       }
-      // TODO(floitsch): compileVariable temporarily returns primitives, so
-      // that the rest of the compiler can be adapted incrementally. Therefore
-      // we have to get the constant from the hashtable instead of using the
-      // returned result directly.
-      constantHandler.compileVariable(element);
-      return constantHandler.initialVariableValues[element];
+      return constantHandler.compileVariable(element);
     } else if (send.isPrefix) {
       assert(send.isOperator);
       Constant receiverConstant = evaluate(send.receiver);
       Operator op = send.selector;
       Constant folded = receiverConstant.unaryFold(op.source.stringValue);
       if (folded === null) error(send);
       return folded;
     } else if (send.isOperator && !send.isPostfix) {
       assert(send.argumentCount() == 1);
       Constant left = evaluate(send.receiver);
@@ skipping 33 matching lines @@
                                                      arguments);
   }
 
   error(Node node) {
     // TODO(floitsch): get the list of constants that are currently compiled
     // and present some kind of stack-trace.
     MessageKind kind = MessageKind.NOT_A_COMPILE_TIME_CONSTANT;
     compiler.reportError(node, new CompileTimeConstantError(kind, const []));
   }
 }