Implement ES6 Template Literals

src/parser.cc

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/v8.h"
 
 #include "src/api.h"
 #include "src/ast.h"
 #include "src/bailout-reason.h"
 #include "src/base/platform/platform.h"
@@ skipping 797 matching lines @@
       pre_parse_timer_(NULL) {
   DCHECK(!script().is_null() || info->source_stream() != NULL);
   set_allow_harmony_scoping(!info->is_native() && FLAG_harmony_scoping);
   set_allow_modules(!info->is_native() && FLAG_harmony_modules);
   set_allow_natives_syntax(FLAG_allow_natives_syntax || info->is_native());
   set_allow_lazy(false);  // Must be explicitly enabled.
   set_allow_arrow_functions(FLAG_harmony_arrow_functions);
   set_allow_harmony_numeric_literals(FLAG_harmony_numeric_literals);
   set_allow_classes(FLAG_harmony_classes);
   set_allow_harmony_object_literals(FLAG_harmony_object_literals);
+  set_allow_harmony_templates(FLAG_harmony_templates);
   for (int feature = 0; feature < v8::Isolate::kUseCounterFeatureCount;
        ++feature) {
     use_counts_[feature] = 0;
   }
   if (info->ast_value_factory() == NULL) {
     // info takes ownership of AstValueFactory.
     info->SetAstValueFactory(
         new AstValueFactory(zone(), parse_info->hash_seed));
   }
 }
@@ skipping 3075 matching lines @@
     reusable_preparser_ = new PreParser(&scanner_, NULL, stack_limit_);
     reusable_preparser_->set_allow_harmony_scoping(allow_harmony_scoping());
     reusable_preparser_->set_allow_modules(allow_modules());
     reusable_preparser_->set_allow_natives_syntax(allow_natives_syntax());
     reusable_preparser_->set_allow_lazy(true);
     reusable_preparser_->set_allow_arrow_functions(allow_arrow_functions());
     reusable_preparser_->set_allow_harmony_numeric_literals(
         allow_harmony_numeric_literals());
     reusable_preparser_->set_allow_classes(allow_classes());
     reusable_preparser_->set_allow_harmony_object_literals(
         allow_harmony_object_literals());

[marja, 2014/11/12 09:23:21]

Here you need to set the allow_templates flag to reusable_preparser as well.

[caitp (gmail), 2014/11/12 13:33:12]

Done.

   }
   PreParser::PreParseResult result =
       reusable_preparser_->PreParseLazyFunction(strict_mode(),
                                                 is_generator(),
                                                 logger);
   if (pre_parse_timer_ != NULL) {
     pre_parse_timer_->Stop();
   }
   return result;
 }
@@ skipping 1098 matching lines @@
   info()->SetFunction(result);
 
   // We cannot internalize on a background thread; a foreground task will take
   // care of calling Parser::Internalize just before compilation.
 
   if (compile_options() == ScriptCompiler::kProduceParserCache) {
     if (result != NULL) *info_->cached_data() = recorder.GetScriptData();
     log_ = NULL;
   }
 }
+
+
+ParserTraits::TemplateLiteralState Parser::OpenTemplateLiteral(int pos) {
+  return new (zone()) ParserTraits::TemplateLiteral(zone(), pos);
+}
+
+
+void Parser::AddTemplateSpan(TemplateLiteralState* state, bool tail) {
+  int pos = scanner()->location().beg_pos;
+  int end = scanner()->location().end_pos - (tail ? 1 : 2);
+  const AstRawString* tv = scanner()->CurrentSymbol(ast_value_factory());
+  Literal* cooked = factory()->NewStringLiteral(tv, pos);
+  (*state)->AddTemplateSpan(cooked, end, zone());
+}
+
+
+void Parser::AddTemplateExpression(TemplateLiteralState* state,
+                                   Expression* expression) {
+  (*state)->AddExpression(expression, zone());
+}
+
+
+Expression* Parser::CloseTemplateLiteral(TemplateLiteralState* state,
+                                         int start, Expression* tag) {
+#define COOKED_STRING(i) cookedStrings->at(i)
+#define POS(i) cookedStrings->at(i)->position()
+#define EXPR(i) expressions->at(i)
+  TemplateLiteral* lit = *state;
+  int pos = lit->position();
+  const ZoneList<Expression*>* cookedStrings = lit->cooked();

[marja, 2014/11/12 09:23:21]

Style: cookedStrings -> cooked_strings (+ other variables elsewhere)

[caitp (gmail), 2014/11/12 13:33:12]

Done.

+  const ZoneList<Expression*>* expressions = lit->expressions();
+  CHECK(cookedStrings->length() == (expressions->length() + 1));
+
+  if (!tag) {
+    // Build tree of BinaryOps to simplify code-generation
+    Expression* expr = NULL;
+
+    if (!expressions->length()) {

[marja, 2014/11/12 09:23:21]

Style nit: if (expressions->length() == 0)

[caitp (gmail), 2014/11/12 13:33:12]

Done.

+      // Simple case: treat as string literal
+      expr = COOKED_STRING(0);
+    } else {
+      int i;
+      expr = factory()->NewBinaryOperation(Token::ADD,
+          COOKED_STRING(0), EXPR(0), POS(0));
+      for (i = 1; i < expressions->length(); ++i) {
+        expr = factory()->NewBinaryOperation(Token::ADD,
+            expr, factory()->NewBinaryOperation(Token::ADD, COOKED_STRING(i),
+            EXPR(i), POS(i)), POS(i));
+      }
+      expr = factory()->NewBinaryOperation(Token::ADD, expr, COOKED_STRING(i),
+          POS(i));
+    }
+    return expr;
+  } else {
+    const ZoneList<int>* lengths = lit->lengths();
+    ZoneList<Expression*>* rawStrings = new (zone()) ZoneList<Expression*>(

[marja, 2014/11/12 09:23:21]

raw_strings

+        cookedStrings->length(), zone());
+    Handle<String> source(String::cast(script()->source()));
+
+    // Build raw strings
+    for (int i = 0; i < cookedStrings->length(); ++i) {

[marja, 2014/11/12 09:23:21]

Gets confusing with i, c and j; could you rename i to string_index or sth, then
j could be raw_chars_from_index and c could be raw_chars_to_index. Or something
along those lines.

[caitp (gmail), 2014/11/12 13:33:12]

Done. (I'm not sure this is much easier to read, though)

[marja, 2014/11/12 13:41:14]

Yeah, they're kinda long. How about just to_index and from_index? Or to and
from?

+      int offset = POS(i);
+      int length = lengths->at(i);
+      SmartArrayPointer<char> rawChars = source->ToCString(
+          ALLOW_NULLS, FAST_STRING_TRAVERSAL, offset + 1, length - 1, &length);
+      int c = 0;
+      int j = 0;
+
+      // Normalize line endings

[marja, 2014/11/12 09:23:21]

You could expand this comment to say what exactly is changed to what. It's not
trivial to see from the code below.... \r\n is changed to \n, right?

[caitp (gmail), 2014/11/12 13:33:12]

Done.

+      for (; j < length; ++j) {
+        char ch = rawChars[j];
+        if (ch == '\r') {
+          rawChars[c++] = '\n';
+          if (j < length - 1 && rawChars[j + 1] == '\n') {
+            ++j;
+          }
+        } else {
+          rawChars[c++] = ch;
+        }
+      }
+      rawStrings->Add(factory()->NewStringLiteral(
+          ast_value_factory()->GetOneByteString(
+              OneByteVector(rawChars.get(), c)), offset), zone());
+    }
+

[marja, 2014/11/12 09:23:21]

I like this version of raw string building thing better than the previous
version, since this is localized: this quirk of templates doesn't leak to all
places where we handle literals.

+    int cooked_idx = function_state_->NextMaterializedLiteralIndex();
+    int raw_idx = function_state_->NextMaterializedLiteralIndex();
+
+    // GetTemplateCallSite
+    ZoneList<Expression*>* args = new (zone()) ZoneList<Expression*>(4, zone());
+    args->Add(factory()->NewArrayLiteral(
+        const_cast<ZoneList<Expression*>*>(cookedStrings), cooked_idx, pos),
+        zone());
+    args->Add(factory()->NewArrayLiteral(
+        const_cast<ZoneList<Expression*>*>(rawStrings), raw_idx, pos), zone());
+    this->CheckPossibleEvalCall(tag, scope_);
+    Expression* expr = factory()->NewCallRuntime(
+        ast_value_factory()->get_template_callsite_string(), NULL, args, start);
+
+    // Call TagFn
+    ZoneList<Expression*>* callArgs = new (zone()) ZoneList<Expression*>(

[marja, 2014/11/12 09:23:21]

call_args

+        expressions->length() + 1, zone());
+    callArgs->Add(expr, zone());
+    callArgs->AddAll(*expressions, zone());
+    expr = factory()->NewCall(tag, callArgs, pos);
+    return expr;
+  }
+#undef COOKED_STRING
+#undef POS
+#undef EXPR
+}
+
 } }  // namespace v8::internal