refactor(transpiler): split the monolithic dart transformer

fixes #24

The new architecture conforms with the Traceur architecture.

tools/transpiler/src/codegeneration/ClassTransformer.js

@@ -0,0 +1,68 @@
+import {ParseTreeTransformer} from 'traceur/src/codegeneration/ParseTreeTransformer';
+
+import {
+  PROPERTY_METHOD_ASSIGNMENT,
+  MEMBER_EXPRESSION,
+  THIS_EXPRESSION,
+  BINARY_EXPRESSION
+} from 'traceur/src/syntax/trees/ParseTreeType';
+
+import {CONSTRUCTOR} from 'traceur/src/syntax/PredefinedName';
+
+import {propName} from 'traceur/src/staticsemantics/PropName';
+
+import {ClassFieldParseTree} from '../ast/class_field';
+
+/**
+ * Transforms class declaration:
+ * - rename constructor (name of the class - default Dart constructor)
+ *
+ */
+
+export class ClassTransformer extends ParseTreeTransformer {
+  /**
+   * @param {ClassDeclaration} tree
+   * @returns {ParseTree}
+   */
+  transformClassDeclaration(tree) {
+    var className = tree.name.identifierToken.toString();
+    var argumentTypesMap = {};
+    var fields = [];
+
+    tree.elements.forEach(function(elementTree) {
+      if (elementTree.type === PROPERTY_METHOD_ASSIGNMENT &&
+          !elementTree.isStatic &&
+          propName(elementTree) === CONSTRUCTOR) {
+
+        // Store constructor argument types,
+        // so that we can use them to set the types of simple-assigned fields.
+        elementTree.parameterList.parameters.forEach(function(p) {
+          var binding = p.parameter.binding;
+          if (binding.identifierToken) {
+            argumentTypesMap[binding.identifierToken.value] = p.typeAnnotation;
+          }
+        });
+
+        // Rename "constructor" to the class name.
+        elementTree.name.literalToken.value = className;
+
+        // Collect all fields, defined in the constructor.
+        elementTree.body.statements.forEach(function(statement) {
+          if (statement.expression.type === BINARY_EXPRESSION &&
+              statement.expression.operator.type === '=' &&
+              statement.expression.left.type === MEMBER_EXPRESSION &&
+              statement.expression.left.operand.type === THIS_EXPRESSION) {
+
+            var typeAnnotation = argumentTypesMap[statement.expression.left.memberName.value] || null;
+            fields.push(new ClassFieldParseTree(tree.location, statement.expression.left.memberName, typeAnnotation));
+          }
+        });
+      }
+    });
+
+    // Add the field definitions to the beginning of the class.
+    tree.elements = fields.concat(tree.elements);
+
+    return super(tree);
+  };
+}

tools/transpiler/src/codegeneration/DartTransformer.js

@@ -0,0 +1,28 @@
+import {MultiTransformer} from 'traceur/src/codegeneration/MultiTransformer';
+import {UniqueIdentifierGenerator} from 'traceur/src/codegeneration/UniqueIdentifierGenerator';
+import {options} from 'traceur/src/Options';
+
+import {ClassTransformer} from './ClassTransformer';
+import {InstanceOfTransformer} from './InstanceOfTransformer';
+import {MultiVarTransformer} from './MultiVarTransformer';
+import {StrictEqualityTransformer} from './StrictEqualityTransformer';
+
+/**
+ * Transforms ES6 + annotations to Dart code.
+ */
+export class DartTransformer extends MultiTransformer {
+  constructor(reporter, idGenerator = new UniqueIdentifierGenerator()) {
+    super(reporter, options.validate);
+
+    var append = (transformer) => {
+      this.append((tree) => {
+        return new transformer(idGenerator, reporter).transformAny(tree);
+      });
+    };
+
+    append(MultiVarTransformer);
+    append(InstanceOfTransformer);
+    append(StrictEqualityTransformer);
+    append(ClassTransformer);
+  }
+}

tools/transpiler/src/codegeneration/InstanceOfTransformer.js

@@ -0,0 +1,25 @@
+import {INSTANCEOF} from 'traceur/src/syntax/TokenType';
+
+import {ParseTreeTransformer} from 'traceur/src/codegeneration/ParseTreeTransformer';
+
+/**
+ * Transforms `a instanceof b` to `a is b`,
+ */
+export class InstanceOfTransformer extends ParseTreeTransformer {
+  /**
+   * @param {BinaryExpression} tree
+   * @return {ParseTree}
+   */
+  transformBinaryExpression(tree) {
+    tree.left = this.transformAny(tree.left);
+    tree.right = this.transformAny(tree.right);
+
+    if (tree.operator.type === 'instanceof') {
+      // TODO(vojta): do this in a cleaner way.
+      tree.operator.type = 'is';
+      return tree;
+    }
+
+    return tree;
+  }
+}

tools/transpiler/src/codegeneration/MultiVarTransformer.js

@@ -0,0 +1,46 @@
+import {VariableStatement, VariableDeclarationList} from 'traceur/src/syntax/trees/ParseTrees';
+
+import {ParseTreeTransformer} from 'traceur/src/codegeneration/ParseTreeTransformer';
+
+/**
+ * Transforms `var a, b;` to `var a; var b;`
+ */
+export class MultiVarTransformer extends ParseTreeTransformer {
+  // Individual item transformer can return an array of items.
+  // This is used in `transformVariableStatement`.
+  // Otherwise this is copy/pasted from `ParseTreeTransformer`.
+  transformList(list) {
+    var transformedList = [];
+    var transformedItem = null;
+
+    for (var i = 0, ii = list.length; i < ii; i++) {
+      transformedItem = this.transformAny(list[i]);
+      if (Array.isArray(transformedItem)) {
+        transformedList = transformedList.concat(transformedItem);
+      } else {
+        transformedList.push(transformedItem);
+      }
+    }
+
+    return transformedList;
+  }
+
+  /**
+   * @param {VariableStatement} tree
+   * @returns {ParseTree}
+   */
+  transformVariableStatement(tree) {
+    var declarations = tree.declarations.declarations;
+
+    if (declarations.length === 1 || declarations.length === 0) {
+      return tree;
+    }
+
+    // Multiple var declaration, we will split it into multiple statements.
+    // TODO(vojta): We can leave the multi-definition as long as they are all the same type/untyped.
+    return declarations.map(function(declaration) {
+      return new VariableStatement(tree.location, new VariableDeclarationList(tree.location,
+          tree.declarations.declarationType, [declaration]));
+    });
+  }
+}

tools/transpiler/src/codegeneration/StrictEqualityTransformer.js

@@ -0,0 +1,42 @@
+import {
+  createCallExpression,
+  createIdentifierExpression,
+  createArgumentList} from 'traceur/src/codegeneration/ParseTreeFactory';
+
+import {
+  EQUAL_EQUAL_EQUAL,
+  NOT_EQUAL_EQUAL
+} from 'traceur/src/syntax/TokenType';
+
+import {ParseTreeTransformer} from 'traceur/src/codegeneration/ParseTreeTransformer';
+
+/**
+ * Transforms:
+ * - `a === b` to `indentical(a, b)`,
+ * - `a !== b` to `!identical(a, b)`
+ */
+export class StrictEqualityTransformer extends ParseTreeTransformer {
+  /**
+   * @param {BinaryExpression} tree
+   * @return {ParseTree}
+   */
+  transformBinaryExpression(tree) {
+    tree.left = this.transformAny(tree.left);
+    tree.right = this.transformAny(tree.right);
+
+    if (tree.operator.type === EQUAL_EQUAL_EQUAL) {
+      // `a === b` -> `identical(a, b)`
+      return createCallExpression(createIdentifierExpression('identical'),
+                                  createArgumentList([tree.left, tree.right]));
+    }
+
+    if (tree.operator.type === NOT_EQUAL_EQUAL) {
+      // `a !== b` -> `!identical(a, b)`
+      // TODO(vojta): do this in a cleaner way.
+      return createCallExpression(createIdentifierExpression('!identical'),
+                                  createArgumentList([tree.left, tree.right]));
+    }
+
+    return tree;
+  }
+}

tools/transpiler/src/compiler.js

@@ -1,5 +1,5 @@
 import {Compiler as TraceurCompiler} from 'traceur/src/Compiler';
-import {ClassTransformer} from './dart_class_transformer';
+import {DartTransformer} from './codegeneration/DartTransformer';
 import {DartTreeWriter} from './dart_writer';
 import {CollectingErrorReporter} from 'traceur/src/util/CollectingErrorReporter';
 import {Parser} from './parser';
@@ -16,8 +16,11 @@ export class Compiler extends TraceurCompiler {
 
   transform(tree, moduleName = undefined) {
     if (this.options_.outputLanguage.toLowerCase() === 'dart') {
-      var transformer = new ClassTransformer();
+      var errorReporter = new CollectingErrorReporter();
-      return transformer.transformAny(tree);
+      var transformer = new DartTransformer(errorReporter);
+      var transformedTree = transformer.transform(tree);
+      this.throwIfErrors(errorReporter);
+      return transformedTree;
     } else {
       return super(tree, moduleName);
     }

tools/transpiler/src/dart_class_transformer.js

@@ -1,124 +0,0 @@
-import {ParseTreeTransformer} from 'traceur/src/codegeneration/ParseTreeTransformer';
-import {createVariableStatement, createCallExpression, createIdentifierExpression, createArgumentList} from 'traceur/src/codegeneration/ParseTreeFactory';
-
-// var token = traceur.syntax.TokenType;
-// var CONSTRUCTOR = token.CONSTRUCTOR;
-
-import {PROPERTY_METHOD_ASSIGNMENT, MEMBER_EXPRESSION, THIS_EXPRESSION, BINARY_EXPRESSION} from 'traceur/src/syntax/trees/ParseTreeType';
-import {EQUAL_EQUAL_EQUAL, NOT_EQUAL_EQUAL} from 'traceur/src/syntax/TokenType';
-import {CONSTRUCTOR} from 'traceur/src/syntax/PredefinedName';
-
-import {VariableStatement, VariableDeclarationList} from 'traceur/src/syntax/trees/ParseTrees';
-
-import {propName} from 'traceur/src/staticsemantics/PropName';
-
-import {ClassFieldParseTree} from './ast/class_field';
-
-// - rename constructor (name of the class - default Dart constructor)
-export class ClassTransformer extends ParseTreeTransformer {
-  // Transform multi-var declarations, into multiple statements:
-  // var x, y;
-  // ==>
-  // var x;
-  // var y;
-  // TODO(vojta): move this into a separate transformer.
-
-  // Individual item transformer can return an array of items.
-  // This is used in `transformVariableStatement`.
-  // Otherwise this is copy/pasted from `ParseTreeTransformer`.
-  transformList(list) {
-    var transformedList = [];
-    var transformedItem = null;
-
-    for (var i = 0, ii = list.length; i < ii; i++) {
-      transformedItem = this.transformAny(list[i]);
-      if (Array.isArray(transformedItem)) {
-        transformedList = transformedList.concat(transformedItem);
-      } else {
-        transformedList.push(transformedItem);
-      }
-    }
-
-    return transformedList;
-  }
-
-  transformVariableStatement(tree) {
-    var declarations = tree.declarations.declarations;
-
-    if (declarations.length === 1 || declarations.length === 0) {
-      return tree;
-    }
-
-    // Multiple var declaration, we will split it into multiple statements.
-    // TODO(vojta): We can leave the multi-definition as long as they are all the same type/untyped.
-    return declarations.map(function(declaration) {
-      return new VariableStatement(tree.location, new VariableDeclarationList(tree.location,
-          tree.declarations.declarationType, [declaration]));
-    });
-  }
-
-
-  // Transform triple equals into identical() call.
-  // TODO(vojta): move to a separate transformer
-  transformBinaryExpression(tree) {
-    tree.left = this.transformAny(tree.left);
-    tree.right = this.transformAny(tree.right);
-    if (tree.operator.type === 'instanceof') {
-      // a instanceof b -> a is b
-      // TODO(vojta): do this in a cleaner way.
-      tree.operator.type = 'is';
-      return tree;
-    } else if (tree.operator.type === EQUAL_EQUAL_EQUAL) {
-      // a === b -> identical(a, b)
-      return createCallExpression(createIdentifierExpression('identical'), createArgumentList([tree.left, tree.right]));
-    } else if (tree.operator.type === NOT_EQUAL_EQUAL) {
-      // a !== b -> !identical(a, b)
-      // TODO(vojta): do this in a cleaner way.
-      return createCallExpression(createIdentifierExpression('!identical'), createArgumentList([tree.left, tree.right]));
-    } else {
-      return tree;
-    }
-  };
-
-  transformClassDeclaration(tree) {
-    var className = tree.name.identifierToken.toString();
-    var argumentTypesMap = {};
-    var fields = [];
-
-    tree.elements.forEach(function(elementTree) {
-      if (elementTree.type === PROPERTY_METHOD_ASSIGNMENT &&
-          !elementTree.isStatic &&
-          propName(elementTree) === CONSTRUCTOR) {
-
-        // Store constructor argument types,
-        // so that we can use them to set the types of simple-assigned fields.
-        elementTree.parameterList.parameters.forEach(function(p) {
-          var binding = p.parameter.binding;
-          if (binding.identifierToken) {
-            argumentTypesMap[binding.identifierToken.value] = p.typeAnnotation;
-          }
-        });
-
-        // Rename "constructor" to the class name.
-        elementTree.name.literalToken.value = className;
-
-        // Collect all fields, defined in the constructor.
-        elementTree.body.statements.forEach(function(statement) {
-          if (statement.expression.type === BINARY_EXPRESSION &&
-              statement.expression.operator.type === '=' &&
-              statement.expression.left.type === MEMBER_EXPRESSION &&
-              statement.expression.left.operand.type === THIS_EXPRESSION) {
-
-            var typeAnnotation = argumentTypesMap[statement.expression.left.memberName.value] || null;
-            fields.push(new ClassFieldParseTree(tree.location, statement.expression.left.memberName, typeAnnotation));
-          }
-        });
-      }
-    });
-
-    // Add the field definitions to the begining of the class.
-    tree.elements = fields.concat(tree.elements);
-
-    return super(tree);
-  };
-}