feat(i18n): add custom placeholder names

Closes #7799

Closes #8057

modules/angular2/src/compiler/expression_parser/lexer.ts

@@ -145,7 +145,7 @@ export const $BACKSLASH = 92;
 export const $RBRACKET = 93;
 const $CARET = 94;
 const $_ = 95;
-
+export const $BT = 96;
 const $a = 97, $e = 101, $f = 102, $n = 110, $r = 114, $t = 116, $u = 117, $v = 118, $z = 122;
 
 export const $LBRACE = 123;
@@ -415,6 +415,10 @@ function isExponentSign(code: number): boolean {
   return code == $MINUS || code == $PLUS;
 }
 
+export function isQuote(code: number): boolean {
+  return code === $SQ || code === $DQ || code === $BT;
+}
+
 function unescape(code: number): number {
   switch (code) {
     case $n:

modules/angular2/src/compiler/expression_parser/parser.ts

@@ -6,6 +6,7 @@ import {
   Lexer,
   EOF,
   isIdentifier,
+  isQuote,
   Token,
   $PERIOD,
   $COLON,
@@ -16,7 +17,8 @@ import {
   $LBRACE,
   $RBRACE,
   $LPAREN,
-  $RPAREN
+  $RPAREN,
+  $SLASH
 } from './lexer';
 import {
   AST,
@@ -67,7 +69,7 @@ export class Parser {
 
   parseAction(input: string, location: any): ASTWithSource {
     this._checkNoInterpolation(input, location);
-    var tokens = this._lexer.tokenize(input);
+    var tokens = this._lexer.tokenize(this._stripComments(input));
     var ast = new _ParseAST(input, location, tokens, true).parseChain();
     return new ASTWithSource(ast, input, location);
   }
@@ -96,7 +98,7 @@ export class Parser {
     }
 
     this._checkNoInterpolation(input, location);
-    var tokens = this._lexer.tokenize(input);
+    var tokens = this._lexer.tokenize(this._stripComments(input));
     return new _ParseAST(input, location, tokens, false).parseChain();
   }
 
@@ -122,7 +124,7 @@ export class Parser {
     let expressions = [];
 
     for (let i = 0; i < split.expressions.length; ++i) {
-      var tokens = this._lexer.tokenize(split.expressions[i]);
+      var tokens = this._lexer.tokenize(this._stripComments(split.expressions[i]));
       var ast = new _ParseAST(input, location, tokens, false).parseChain();
       expressions.push(ast);
     }
@@ -158,6 +160,28 @@ export class Parser {
     return new ASTWithSource(new LiteralPrimitive(input), input, location);
   }
 
+  private _stripComments(input: string): string {
+    let i = this._commentStart(input);
+    return isPresent(i) ? input.substring(0, i).trim() : input;
+  }
+
+  private _commentStart(input: string): number {
+    var outerQuote = null;
+    for (var i = 0; i < input.length - 1; i++) {
+      let char = StringWrapper.charCodeAt(input, i);
+      let nextChar = StringWrapper.charCodeAt(input, i + 1);
+
+      if (char === $SLASH && nextChar == $SLASH && isBlank(outerQuote)) return i;
+
+      if (outerQuote === char) {
+        outerQuote = null;
+      } else if (isBlank(outerQuote) && isQuote(char)) {
+        outerQuote = char;
+      }
+    }
+    return null;
+  }
+
   private _checkNoInterpolation(input: string, location: any): void {
     var parts = StringWrapper.split(input, INTERPOLATION_REGEXP);
     if (parts.length > 1) {