Renamed symbolTable to runtime. Implemented 'return' keyword function…

…ality.
luizfar · Apr 23, 2011 · 6e006e0 · 6e006e0
1 parent 8725c59
commit 6e006e0
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Showing 12 changed files with 143 additions and 99 deletions.
diff --git a/runner.html b/runner.html
@@ -2,9 +2,9 @@
   <head>
     <script src="lib/jquery.min.js"></script>
     <script src="src/bootstrap.js"></script>
+    <script src="src/runtime.js"></script>
     <script src="src/util.js"></script>
     <script src="src/symbol.js"></script>
-    <script src="src/symbolTable.js"></script>
     <script src="src/lexer.js"></script>
     <script src="src/functionParser.js"></script>
     <script src="src/classParser.js"></script>
@@ -15,11 +15,17 @@
     <script src="src/jazz.js"></script>
 
     <script type="jazz">
-      x = 2
-      if x is 3
-        log "=="
-      log "done"
+      f = (param) {
+        if param
+          return "param is true"
+        else
+          return "param is false"
+        log "not here"
+      }
+      log f(true)
+      log f(false)
     </script>
+
       x = 1 + 1
       y = x * 2 - 3 * 2
       log "-3 : " + y.add(-4).add(5).multiply(3)

diff --git a/spec/SpecRunner.html b/spec/SpecRunner.html
@@ -10,9 +10,9 @@
   <!-- include source files here... -->
   <script src="../lib/jquery.min.js"></script>
   <script src="../src/bootstrap.js"></script>
+  <script src="../src/runtime.js"></script>
   <script src="../src/util.js"></script>
   <script src="../src/symbol.js"></script>
-  <script src="../src/symbolTable.js"></script>
   <script src="../src/lexer.js"></script>
   <script src="../src/functionParser.js"></script>
   <script src="../src/classParser.js"></script>

diff --git a/spec/jazz.function.spec.js b/spec/jazz.function.spec.js
@@ -33,5 +33,19 @@ describe("Jazz interpreter for Object's methods", function () {
       'f("hey")("you")');
     expect(console.content).toEqual("hey\nyou");
   });
+
+  it("should return from a function when a return statement is executed", function () {
+    jazz.execute(
+      'f = (param) {\n' + 
+      '  if param\n' +
+      '    return "param is true"\n' +
+      '  else\n' +
+      '    return "param is false"\n' +
+      '  log "not here"\n' +
+      '}\n' +
+      'log f(true)\n' +
+      'log f(false)');
+    expect(console.content).toEqual("param is true\nparam is false");
+  });
 
 });
diff --git a/src/classParser.js b/src/classParser.js
@@ -1,6 +1,6 @@
 var jazz = jazz || {};
 
-jazz.ClassParser = function (lexer, symbolTable, functionParser, exprParser) {  
+jazz.ClassParser = function (lexer, runtime, functionParser, exprParser) {  
   var util = jazz.util;
   var symbol = jazz.symbol;
 
@@ -16,7 +16,7 @@ jazz.ClassParser = function (lexer, symbolTable, functionParser, exprParser) {
     }
     lexer.checkAndConsumeToken(symbol.RIGHT_CUR);
     return function () {
-      symbolTable.addClass(clazz);
+      runtime.addClass(clazz);
     }
   };
 }
diff --git a/src/expressionParser.js b/src/expressionParser.js
@@ -1,9 +1,9 @@
 var jazz = jazz || {};
 
-jazz.ExpressionParser = function (lexer, symbolTable) {
-  var functionParser = new jazz.FunctionParser(lexer, symbolTable, this);
-  var classParser = new jazz.ClassParser(lexer, symbolTable, functionParser, this);
-  var objectParser = new jazz.ObjectParser(lexer, symbolTable, this);
+jazz.ExpressionParser = function (lexer, runtime) {
+  var functionParser = new jazz.FunctionParser(lexer, runtime, this);
+  var classParser = new jazz.ClassParser(lexer, runtime, functionParser, this);
+  var objectParser = new jazz.ObjectParser(lexer, runtime, this);
 
   var symbol = jazz.symbol;
   var operations = jazz.operations;
@@ -67,6 +67,9 @@ jazz.ExpressionParser = function (lexer, symbolTable) {
       case symbol.IF:
         return parseIf();
 
+      case symbol.RETURN:
+        return parseReturn();
+
       case symbol.CLASS:
         return classParser.parseClass();
 
@@ -97,6 +100,16 @@ jazz.ExpressionParser = function (lexer, symbolTable) {
     };
   }
 
+  function parseReturn () {
+    lexer.next();
+    var expression = parseExpression();
+    return function () {
+      var returnValue = expression();
+      runtime.clearExpressions();
+      return returnValue;
+    };
+  }
+
   function parseAlert() {
     lexer.next();
     var expression = parseOrExpression();
@@ -263,12 +276,12 @@ jazz.ExpressionParser = function (lexer, symbolTable) {
       lexer.next();
       var expression = parseExpression();
       return function () {
-        var variable = symbolTable.getOrCreate(variableName);
+        var variable = runtime.getOrCreate(variableName);
         variable.value = expression();
       };
     }
     return function () {
-      var variable = symbolTable.get(variableName);
+      var variable = runtime.get(variableName);
       return variable.value;
     };
   }

diff --git a/src/functionParser.js b/src/functionParser.js
@@ -1,6 +1,6 @@
 var jazz = jazz || {};
 
-jazz.FunctionParser = function (lexer, symbolTable, expressionParser) {
+jazz.FunctionParser = function (lexer, runtime, expressionParser) {
   var util = jazz.util;
   var symbol = jazz.symbol;
 
@@ -43,19 +43,22 @@ jazz.FunctionParser = function (lexer, symbolTable, expressionParser) {
     }
     lexer.next();
     _function.invoke = function (receiver, args) {
-      symbolTable.addScope();
+      runtime.addContext();
       util.each(_function.params, function (param, index) {
-        symbolTable.add({
+        runtime.add({
           name: param,
-          value: typeof args[index] !== "undefined" ? args[index] : jazz.lang.Null.init()
+          value: typeof args[index] !== "undefined" ? args[index] : jazz.lang.Null.NULL_OBJECT
         });
       });
-      var lastValue = jazz.lang.Null.init();
-      util.each(this.expressions, function (expression) {
-        lastValue = expression();
-      });
-      symbolTable.removeScope();
-      return lastValue;
+      var returnValue = jazz.lang.Null.NULL_OBJECT;
+      runtime.setExpressions(_function.expressions);
+      var expression = runtime.removeExpression();
+      while (expression) {
+        returnValue = expression();
+        expression = runtime.removeExpression();
+      }
+      runtime.removeContext();
+      return returnValue;
     }
     return _function;
   }

diff --git a/src/interpreter.js b/src/interpreter.js
@@ -3,10 +3,10 @@ var jazz = jazz || {};
 jazz.Interpreter = function (input) {
 
   var lexer = new jazz.Lexer(input);
-  var symbolTable = new jazz.SymbolTable();
-  var parser = new jazz.Parser(lexer, symbolTable);
+  var runtime = new jazz.Runtime();
+  var parser = new jazz.Parser(lexer, runtime);
 
-  symbolTable.addClass(jazz.lang.Class);
+  runtime.addClass(jazz.lang.Class);
 
   this.start = function () {
     lexer.next();

diff --git a/src/objectParser.js b/src/objectParser.js
@@ -1,6 +1,6 @@
 var jazz = jazz || {};
 
-jazz.ObjectParser = function (lexer, symbolTable, expressionParser) {
+jazz.ObjectParser = function (lexer, runtime, expressionParser) {
   var util = jazz.util;
   var symbol = jazz.symbol;
 

diff --git a/src/parser.js b/src/parser.js
@@ -1,7 +1,7 @@
 var jazz = jazz || {};
 
-jazz.Parser = function (lexer, symbolTable) {
-  var exprParser = new jazz.ExpressionParser(lexer, symbolTable);
+jazz.Parser = function (lexer, runtime) {
+  var exprParser = new jazz.ExpressionParser(lexer, runtime);
 
   this.start = function () {
     do {

diff --git a/src/runtime.js b/src/runtime.js
@@ -0,0 +1,75 @@
+var jazz = jazz || {};
+
+jazz.Runtime = function () {
+  var contexts = [];
+  var contextIndex = 0;
+  var currentContext = emptyContext();
+
+  contexts[contextIndex] = currentContext;
+
+  function emptyContext() {
+    return {
+      variables: {},
+      expressions: [],
+      exprIndex: undefined
+    };
+  }
+
+  this.addClass = function(clazz) {
+    this.add({
+      type: jazz.lang.Class,
+      value: clazz,
+      name: clazz.name
+    });
+  };
+
+  this.add = function (variable) {
+    if (currentContext.variables[variable.name]) {
+      jazz.util.error("Identifier '" + variable.name + "' already in use.");
+    } else {
+      currentContext.variables[variable.name] = variable;
+    }
+  };
+
+  this.getOrCreate = function (variableName) {
+    var variable = currentContext.variables[variableName];
+    if (!variable) {
+      variable = { name: variableName, value: jazz.lang.Null.init() };
+      currentContext.variables[variableName] = variable;
+    }
+    return variable;
+  }
+
+  this.get = function (identifier) {
+    for (var i = contextIndex; i >= 0; --i) {
+      var variable = contexts[i].variables[identifier];
+      if (variable) {
+        return variable;
+      }
+    }
+    jazz.util.error("Unknown identifier: " + identifier);
+  };
+
+  this.setExpressions = function (expressions) {
+    currentContext.expressions = expressions;
+    currentContext.exprIndex = 0;
+  };
+
+  this.removeExpression = function () {
+    return currentContext.expressions[currentContext.exprIndex++];
+  };
+
+  this.clearExpressions = function () {
+    currentContext.exprIndex = currentContext.expressions.length;
+  }
+
+  this.addContext = function () {
+    currentContext = emptyContext();
+    contexts[++contextIndex] = currentContext;
+  };
+
+  this.removeContext = function () {
+    currentContext = contexts[--contextIndex];
+    delete contexts[contextIndex + 1];
+  };
+}
diff --git a/src/symbol.js b/src/symbol.js
@@ -29,7 +29,8 @@ jazz.symbol = {
   LOG: "log",
   OR: "or",
   TRUE: "true",
-  FALSE: "false"
+  FALSE: "false",
+  RETURN: "return"
 };
 
 (function () {

diff --git a/src/symbolTable.js b/src/symbolTable.js