Nit: 10.2.2.2 refers to type by otherwise unmentioned CamelCaps name
In section 10.2.2.2, algorithm step 2 refers to the declarative environment record type by the StUdLyCaPs name DeclarativeEnvironmentRecord, which is never defined or used elsewhere. Perhaps it should simply be declarative environment record, as used elsewhere in the section. ___ es-discuss mailing list es-discuss@mozilla.org https://mail.mozilla.org/listinfo/es-discuss
Re: yield syntax
Igor Bukanov wrote:
2009/5/18 Brendan Eich bren...@mozilla.com:
On May 18, 2009, at 2:25 AM, Igor Bukanov wrote:
The plus side of this is that an empty generator can be created with a
straightforward:
Generator(function() {})
and not with a rather unnatural
(function() { if (false) yield; })()
No one makes empty generators.
For me the problem with the way the generators are defined is that a
dead code like that if (0) yield; affects the semantic by mere
presence of it. Surely, this is not the first feature in ES that has
that property - if (0) var a; is another example. But if (0)
yield; sets a new record affecting the nature of the whole function.
A more explicit alternative is to require some kind of decoration on the
function definition, e.g. (just a straw man):
function generator foo() { ... }
--
David-Sarah Hopwood ⚥
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Re: yield syntax
On May 19, 2009, at 2:00 PM, David-Sarah Hopwood wrote: *If* it is allowed, then it should be two. It would be very surprising if foo(a = b, c); had two arguments (as it does), but the above expression with yield had one. But I agree that it may be better not to allow it. Good; it was a loophole in JS1.7 and up, which I think should be closed. Agreed; this closes the assignment expression loophole. This would disallow foo(yield x); which seems unnecessary. I thought so too, but Python keeps its grammar simple this way, and simpler is better, ceteris paribus. JS1.7 allows this but also suffers the assignment loophole. Getting rid of the latter but not the former is grammar-hacking busy work. I haven't done it in the WebKit/ JavaScriptCore/parser/Grammar.y. /be ___ es-discuss mailing list es-discuss@mozilla.org https://mail.mozilla.org/listinfo/es-discuss
Re: yield syntax
On May 19, 2009, at 2:08 PM, David-Sarah Hopwood wrote:
A more explicit alternative is to require some kind of decoration on
the
function definition, e.g. (just a straw man):
function generator foo() { ... }
Or just (we discussed this briefly last summer in Oslo):
generator foo() { ... }
In JS1.7, we followed Python, which uses def, same as for defining a
function, and distinguishes generators by presence of yield (which
makes value returns illegal). It seems unwise to diverge from Python
without more evidence of an actual usability problem. We have no such
evidence from shipping JS1.7 and up in Firefox 2 and up.
/be
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Techtalk on EcmaScript 5
Waldemar Horwat, Mike Samuel, and I just gave a Google Techtalk on Changes to JavaScript, Part 1: EcmaScript 5. The abstract, bios, and the talk itself are at http://www.youtube.com/watch?v=Kq4FpMe6cRs. The slides are at http://google-caja.googlecode.com/svn/trunk/doc/html/es5-talk/es5-talk.html. I believe this talk is a good introduction to EcmaScript 5 and its rationale. Comments appreciated. Enjoy! -- Cheers, --MarkM ___ es-discuss mailing list es-discuss@mozilla.org https://mail.mozilla.org/listinfo/es-discuss
