I don't see how strict/sloppy mode effects the behavior of top-level lexical declarations. Does the behavior depend on strict mode?
I agree with Brendan: I vote for changing this if we can. Saam > On Aug 31, 2015, at 7:11 PM, Brendan Eich <bren...@mozilla.org> wrote: > > We are in rapid-release hell/heaven. > > This means errata can be issued, and engines can implement the better > resolution for those errata, compared to what the last major-version _de > jure_ spec mandated. > > Why not? > > /be > > Adam Klein wrote: >> Note that this behavior in v8/Chrome is only about sloppy mode. In strict >> mode, v8 implements the ES6 spec (and we'll likely have support for lexical >> declarations in sloppy mode soon). >> >> Though I personally agree that the top-level lexical scoping in ES6 seems >> unfortunate. >> >> On Mon, Aug 31, 2015 at 9:53 AM, Matthew Robb <matthewwr...@gmail.com >> <mailto:matthewwr...@gmail.com>> wrote: >> >> Personally I am a fan of Chrome's CURRENT solution: >> ``` >> Uncaught SyntaxError: Block-scoped declarations (let, const, >> function, class) not yet supported outside strict mode >> ``` >> >> >> - Matthew Robb >> >> On Mon, Aug 31, 2015 at 12:08 PM, Jason Orendorff >> <jason.orendo...@gmail.com <mailto:jason.orendo...@gmail.com>> wrote: >> >> Hi everyone. Can we talk about the global lexical tier? >> >> This was a mistake, a real blunder. We all should have known >> better. >> An extensible intermediate scope implies dynamic scoping. The >> referent >> of an identifier can change only once, but it can change. It's >> like an >> implicit `with` block around *all code*. >> >> This pattern for declaring variable in multiple scripts won't work >> with let/const: >> >> var MyES3Module = MyES3Module || {}; >> >> There's no workaround except "keep using var". >> >> It's now possible to get a binding permanently wedged, which >> is bad for a REPL: >> >> js> let z = Maht.PI; // oops, typo >> ReferenceError: Maht is not defined >> js> z >> ReferenceError: binding is not initialized: "z" >> js> z = 1; >> ReferenceError: binding is not initialized: "z" >> js> delete z; >> false >> js> let z = 1; >> SyntaxError: redeclaration of variable: "z" >> >> For a single name to have two global bindings, both mutable, >> is astonishing. >> >> All of this was unnecessary. What's the benefit to users? We ran >> roughshod over existing practice, invariants, and expectations in >> order to obtain a kind of self-consistency for `let` that >> users don't >> expect or even care about. >> >> We should have just made toplevel let/const/class create global >> properties, like var. This is how it was proposed originally >> and how >> Babel implements it today. For SpiderMonkey, switching to the >> worse, >> less user-friendly way without regressing performance is >> time-consuming. >> >> We knew all this. We didn't evaluate it correctly. What we >> particularly missed is that we already had modules as the way >> forward >> to a nice toplevel lexical tier, and weird half measures for >> scripts >> were pointless. >> >> -j >> _______________________________________________ >> es-discuss mailing list >> es-discuss@mozilla.org <mailto:es-discuss@mozilla.org> >> https://mail.mozilla.org/listinfo/es-discuss >> >> >> >> _______________________________________________ >> es-discuss mailing list >> es-discuss@mozilla.org <mailto:es-discuss@mozilla.org> >> https://mail.mozilla.org/listinfo/es-discuss >> >> >> _______________________________________________ >> es-discuss mailing list >> es-discuss@mozilla.org >> https://mail.mozilla.org/listinfo/es-discuss > _______________________________________________ > es-discuss mailing list > es-discuss@mozilla.org > https://mail.mozilla.org/listinfo/es-discuss _______________________________________________ es-discuss mailing list es-discuss@mozilla.org https://mail.mozilla.org/listinfo/es-discuss
