Refresh the implementation of Symbols to catch up with what the
specification now mandates:
* The global Symbol() function manufactures new Symbol values,
optionally with a string description attached.
* Invoking Symbol() as a constructor will now throw.
* ToString() over Symbol values still throws, and
Object.prototype.toString() stringifies like before.
* A Symbol value is wrapped in a Symbol object either implicitly if
it is the receiver, or explicitly done via Object(symbolValue) or
(new Object(symbolValue).)
* The Symbol.prototype.toString() method no longer throws on Symbol
wrapper objects (nor Symbol values.) Ditto for Symbol.prototype.valueOf().
* Symbol.prototype.toString() stringifies as "Symbol("<description>"),
valueOf() returns the wrapper's Symbol value.
* ToPrimitive() over Symbol wrapper objects now throws.
Overall, this provides a stricter separation between Symbol values and
wrapper objects than before, and the explicit fetching out of the
description (nee name) via the "name" property is no longer supported
(by the spec nor the implementation.)
Adjusted existing Symbol test files to fit current, adding some extra
tests for new/changed behavior.
LOG=N
R=arv@chromium.org, rossberg@chromium.org, arv, rossberg
BUG=v8:3053
Review URL: https://codereview.chromium.org/118553003
Patch from Sigbjorn Finne <sigbjornf@opera.com>.
git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@19490 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
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
