Merge pull request #794 from fabiosantoscode/feature/harmony-template-strings-2

Harmony: template strings

lib/parse.js

@@ -114,7 +114,7 @@ var WHITESPACE_CHARS = makePredicate(characters(" \u00a0\n\r\t\f\u000b\u200b\u18
 
 var PUNC_BEFORE_EXPRESSION = makePredicate(characters("[{(,.;:"));
 
-var PUNC_CHARS = makePredicate(characters("[]{}(),;:"));
+var PUNC_CHARS = makePredicate(characters("[]{}(),;:`"));
 
 var REGEXP_MODIFIERS = makePredicate(characters("gmsiy"));
 
@@ -595,6 +595,9 @@ function tokenizer($TEXT, filename, html5_comments) {
         parse_error("Unexpected character '" + ch + "'");
     };
 
+    next_token.next = next;
+    next_token.peek = peek;
+
     next_token.context = function(nc) {
         if (nc) S = nc;
         return S;
@@ -804,6 +807,7 @@ function parse($TEXT, options) {
                 });
               case "[":
               case "(":
+              case "`":
                 return simple_statement();
               case ";":
                 next();
@@ -1333,6 +1337,8 @@ function parse($TEXT, options) {
                 return subscripts(array_(), allow_calls);
               case "{":
                 return subscripts(object_or_object_destructuring_(), allow_calls);
+              case "`":
+                return subscripts(template_string(), allow_calls);
             }
             unexpected();
         }
@@ -1349,6 +1355,38 @@ function parse($TEXT, options) {
         unexpected();
     };
 
+    function template_string() {
+        var tokenizer_S = S.input, start = S.token, segments = [], segment = "", ch;
+
+        while ((ch = tokenizer_S.next()) !== "`")  {
+            if (ch === "$" && tokenizer_S.peek() === "{") {
+                segments.push(segment); segment = "";
+                tokenizer_S.next();
+                next();
+                segments.push(expression());
+                expect("}");
+                if (is("punc", "`")) {
+                    break;
+                }
+                continue;
+            }
+            segment += ch;
+            if (ch === "\\") {
+                segment += tokenizer_S.next();
+            }
+        }
+
+        segments.push(segment);
+
+        next();
+
+        return new AST_TemplateString({
+            start: start,
+            segments: segments,
+            end: S.token
+        });
+    }
+
     function expr_list(closing, allow_trailing_comma, allow_empty) {
         var first = true, a = [];
         while (!is("punc", closing)) {
@@ -1639,6 +1677,13 @@ function parse($TEXT, options) {
             });
             return arrow_function(expr);
         }
+        if ((expr instanceof AST_SymbolRef || expr instanceof AST_PropAccess) && is("punc", "`")) {
+            return new AST_PrefixedTemplateString({
+                start: start,
+                prefix: expr,
+                template_string: template_string()
+            })
+        }
         if (commas && is("punc", ",")) {
             next();
             return new AST_Seq({