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Make let/const outside of the extended mode early errors (under harmony flag).

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The ES.next drafts require that source code that matches the productions for
let and const bindings outside the extended mode trigger early syntax
errors. This CL adapts the parser / preparser accordingly under the harmony
scoping flag.

Summary:
* Harmony scoping flag not set: Old semantics allowing const in classic mode
with function level scope. Const binding in strict mode and let bindings in
classic and strict mode trigger early syntax errors.
* Harmony scoping is set: Use new harmony const and let in
extended mode and old const in classic mode. This is to preserve
compatibility with current web pages that already use
non-standard implementations of const. An early syntax error is
thrown on const in strict mode and on let in classic and strict
mode.

This depends on:
http://codereview.chromium.org/8562002/

TEST=mjsunit/harmony/block-early-errors.js

Review URL: http://codereview.chromium.org/8564001

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@10079 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
This commit is contained in:
keuchel@chromium.org 2011-11-29 06:38:04 +00:00
parent f35e53ff50
commit e26093f3d8
4 changed files with 104 additions and 4 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

1
src/messages.js
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@ -206,6 +206,7 @@ function FormatMessage(message) {
"illegal_break", ["Illegal break statement"],
"illegal_continue", ["Illegal continue statement"],
"illegal_return", ["Illegal return statement"],
"illegal_let", ["Illegal let declaration outside extended mode"],
"error_loading_debugger", ["Error loading debugger"],
"no_input_to_regexp", ["No input to ", "%0"],
"invalid_json", ["String '", "%0", "' is not valid JSON"],

23
src/parser.cc
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@ -1267,6 +1267,7 @@ Statement* Parser::ParseStatement(ZoneStringList* labels, bool* ok) {
return ParseBlock(labels, ok);
case Token::CONST: // fall through
case Token::LET:
case Token::VAR:
stmt = ParseVariableStatement(kStatement, ok);
break;
@ -1708,6 +1709,16 @@ Block* Parser::ParseVariableDeclarations(
if (peek() == Token::VAR) {
Consume(Token::VAR);
} else if (peek() == Token::CONST) {
// TODO(ES6): The ES6 Draft Rev4 section 12.2.2 reads:
//
// ConstDeclaration : const ConstBinding (',' ConstBinding)* ';'
//
// * It is a Syntax Error if the code that matches this production is not
// contained in extended code.
//
// However disallowing const in classic mode will break compatibility with
// existing pages. Therefore we keep allowing const with the old
// non-harmony semantics in classic mode.
Consume(Token::CONST);
switch (top_scope_->language_mode()) {
case CLASSIC_MODE:
@ -1733,7 +1744,17 @@ Block* Parser::ParseVariableDeclarations(
is_const = true;
needs_init = true;
} else if (peek() == Token::LET) {
ASSERT(top_scope_->is_extended_mode());
// ES6 Draft Rev4 section 12.2.1:
//
// LetDeclaration : let LetBindingList ;
//
// * It is a Syntax Error if the code that matches this production is not
// contained in extended code.
if (!is_extended_mode()) {
ReportMessage("illegal_let", Vector<const char*>::empty());
*ok = false;
return NULL;
}
Consume(Token::LET);
if (var_context != kSourceElement &&
var_context != kForStatement) {

29
src/preparser.cc
View File

@ -227,6 +227,7 @@ PreParser::Statement PreParser::ParseStatement(bool* ok) {
return ParseBlock(ok);
case i::Token::CONST:
case i::Token::LET:
case i::Token::VAR:
return ParseVariableStatement(kStatement, ok);
@ -377,6 +378,17 @@ PreParser::Statement PreParser::ParseVariableDeclarations(
if (peek() == i::Token::VAR) {
Consume(i::Token::VAR);
} else if (peek() == i::Token::CONST) {
// TODO(ES6): The ES6 Draft Rev4 section 12.2.2 reads:
//
// ConstDeclaration : const ConstBinding (',' ConstBinding)* ';'
//
// * It is a Syntax Error if the code that matches this production is not
// contained in extended code.
//
// However disallowing const in classic mode will break compatibility with
// existing pages. Therefore we keep allowing const with the old
// non-harmony semantics in classic mode.
Consume(i::Token::CONST);
switch (language_mode()) {
case i::CLASSIC_MODE:
break;
@ -398,9 +410,21 @@ PreParser::Statement PreParser::ParseVariableDeclarations(
require_initializer = true;
break;
}
Consume(i::Token::CONST);
} else if (peek() == i::Token::LET) {
ASSERT(is_extended_mode());
// ES6 Draft Rev4 section 12.2.1:
//
// LetDeclaration : let LetBindingList ;
//
// * It is a Syntax Error if the code that matches this production is not
// contained in extended code.
if (!is_extended_mode()) {
i::Scanner::Location location = scanner_->peek_location();
ReportMessageAt(location.beg_pos, location.end_pos,
"illegal_let", NULL);
*ok = false;
return Statement::Default();
}
Consume(i::Token::LET);
if (var_context != kSourceElement &&
var_context != kForStatement) {
i::Scanner::Location location = scanner_->peek_location();
@ -409,7 +433,6 @@ PreParser::Statement PreParser::ParseVariableDeclarations(
*ok = false;
return Statement::Default();
}
Consume(i::Token::LET);
} else {
*ok = false;
return Statement::Default();

55
test/mjsunit/harmony/block-early-errors.js Normal file
View File

@ -0,0 +1,55 @@
// Copyright 2011 the V8 project authors. All rights reserved.
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are
// met:
//
// * Redistributions of source code must retain the above copyright
// notice, this list of conditions and the following disclaimer.
// * Redistributions in binary form must reproduce the above
// copyright notice, this list of conditions and the following
// disclaimer in the documentation and/or other materials provided
// with the distribution.
// * Neither the name of Google Inc. nor the names of its
// contributors may be used to endorse or promote products derived
// from this software without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
// Flags: --harmony-scoping
function CheckException(e) {
var string = e.toString();
assertInstanceof(e, SyntaxError);
assertTrue(string.indexOf("Illegal let") >= 0);
}
function Check(str) {
try {
eval("(function () { " + str + " })");
assertUnreachable();
} catch (e) {
CheckException(e);
}
try {
eval("(function () { { " + str + " } })");
assertUnreachable();
} catch (e) {
CheckException(e);
}
}
// Check for early syntax errors when using let
// declarations outside of extended mode.
Check("let x;");
Check("let x = 1;");
Check("let x, y;");