feat(DartWriter): support string interpolation

Author: chirayuk

tools/transpiler/spec/lang_spec.js

@@ -0,0 +1,9 @@
+import {describe, it, expect} from 'test_lib/test_lib';
+
+export function main() {
+ describe('lang', function() {
+ it('string interpolation', function() {
+ expect(`${123}-'${456}"`).toEqual('123-\'456"');
+ });
+ });
+}

tools/transpiler/src/dart_writer.js

@@ -1,5 +1,6 @@
 import {CONSTRUCTOR, FROM} from 'traceur/src/syntax/PredefinedName';
-import {EQUAL_EQUAL_EQUAL, OPEN_PAREN, CLOSE_PAREN, IMPORT, SEMI_COLON, STAR, OPEN_CURLY, CLOSE_CURLY, COMMA, AT, EQUAL} from 'traceur/src/syntax/TokenType';
+import {EQUAL_EQUAL_EQUAL, OPEN_PAREN, CLOSE_PAREN, IMPORT, SEMI_COLON, STAR, OPEN_CURLY, CLOSE_CURLY, COMMA, AT,
+ EQUAL, SINGLE_QUOTE} from 'traceur/src/syntax/TokenType';
 
 import {ParseTreeWriter as JavaScriptParseTreeWriter} from 'traceur/src/outputgeneration/ParseTreeWriter';
 
@@ -37,6 +38,17 @@ export class DartTreeWriter extends JavaScriptParseTreeWriter {
  }
  }
 
+ visitTemplateLiteralExpression(tree) {
+ if (tree.operand) {
+ this.visitAny(tree.operand);
+ this.writeSpace_();
+ }
+ this.writeRaw_(SINGLE_QUOTE);
+ this.visitList(tree.elements);
+ this.writeRaw_(SINGLE_QUOTE);
+ }
+
+
  // FUNCTIONS
  // - remove the "function" keyword
  // - type annotation infront