Adds a notion of private symbols, mainly intended for internal use, especially, self-hosting of built-in types that would otherwise require new C++ classes.
On the JS side (i.e., in built-ins), private properties can be created and accessed through a set of macros:
NEW_PRIVATE(print_name)
HAS_PRIVATE(obj, sym)
GET_PRIVATE(obj, sym)
SET_PRIVATE(obj, sym, val)
DELETE_PRIVATE(obj, sym)
In the V8 API, they are accessible via a new class Private, and respective HasPrivate/Get/Private/SetPrivate/DeletePrivate methods on calss Object.
These APIs are designed and restricted such that their implementation can later be replaced by whatever ES7+ will officially provide.
R=yangguo@chromium.org
BUG=
Review URL: https://codereview.chromium.org/48923002
git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@17683 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
(qua last week's TC39)
Specifically:
- Install Symbol constructor function on the global object.
- Adjust code generation for typeof.
- Remove IsSymbol built-in, IS_SYMBOL macro now defined using typeof.
- Remove hack that allowed symbols as constructor results, and some other special cases.
- Remove symbol_delegate and GetDelegate function.
- Extend ToBoolean stub to handle symbols.
- Extend ToNumber to return NaN on symbols.
- Poison symbol's toString function, and thereby ToString on symbols.
R=mstarzinger@chromium.org
BUG=v8:2158
Review URL: https://codereview.chromium.org/12957004
git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@14051 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
Since symbols and strings share a common representation, most of this change is about consistently replacing 'String' with 'Name' in all places where property names are expected. In particular, no new logic at all is necessary for maps, property dictionaries, or transitions. :) The only places where an actual case distinction is needed have to do with generated type checks, and with conversions of names to strings (especially in logger and profiler).
Left in some TODOs wrt to the API: interceptors and native getters don't accept symbols as property names yet, because that would require extending the external v8.h.
(Baseline CL: https://codereview.chromium.org/12296026/)
R=verwaest@chromium.org,mstarzinger@chromium.org
BUG=v8:2158
Review URL: https://codereview.chromium.org/12330012
git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@13811 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
- Add --harmony-symbols flag.
- Add Symbol constructor; allow symbols as (unreplaced) return value from constructors.
- Introduce %CreateSymbol and %_IsSymbol natives and respective instructions.
- Extend 'typeof' code generation to handle symbols.
- Extend CompareIC with a UNIQUE_NAMES state that (uniformly) handles internalized strings and symbols.
- Property lookup delegates to SymbolDelegate object for symbols, which only carries the toString method.
- Extend Object.prototype.toString to recognise symbols.
Per the current draft spec, symbols are actually pseudo objects that are frozen with a null prototype and only one property (toString). For simplicity, we do not treat them as proper objects for now, although typeof will return "object". Only property access works as if they were (frozen) objects (via the internal delegate object).
(Baseline CL: https://codereview.chromium.org/12223071/)
R=mstarzinger@chromium.org
BUG=v8:2158
Review URL: https://codereview.chromium.org/12296026
git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@13786 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
