Quick side note regarding multiple variable declarations: both versions of this proposal (OP's newline-based proposal and the ASI-inspired version) result in code breakage:
``` const x = 5 y = 6 z = 7 ``` Under existing ASI rules, this is currently equivalent to: ``` const x = 5; // y and z are global y = 6; z = 7; ``` If we use newline based comma insertion (or give ASI-style comma insertion precedence over semicolon insertion), then this proposal would result in the following equivalent: ``` const x = 5, // y and z are now lexically scoped constants y = 6, z = 7; ``` Unless I'm missing something, both of those scenarios definitely preclude multiple variable declarations from this proposal. That being said, the ASI-inspired semantics seems like it could have more legs in other contexts, although I would personally argue that too little is offered in exchange for the cognitive overhead of a new rule with ASI-style exceptions attached to it (i.e.., "comma before newlines, except after get, and set, variable declarations, ..."). On Wed, Sep 13, 2017 at 9:57 AM, Naveen Chawla <[email protected]> wrote: > I'm not really familiar with ASI but they key factor mentioned in this > discussion is this (by Claude Pache): > > *A implicit semicolon is not added when a declaration would be complete, > but when the next token would produce a syntax error. * > > By this behaviour (a modification to the initial "complete statement > produces comma" version of this proposal), everything would work perfectly, > no? > > The multi-line get would not produce a comma, and hence the scheme is > backwards compatible, right? > > Please provide a counter-example if I have missed something. > > As for the benefit, the time savings in not having to debug accidentally > omitted commas and not having to add them in the first place are, I think, > an improvement. And of course those who want to continue using commas > everywhere, can: > > ```js > function doStuff( > x > y > z > ){ > } > ``` > > ``` > const > x = 5 > y = 6 > z = 7 > ``` > > Great to hear those counter-examples as I don't know enough about ASI, and > the related subject, to picture the pitfalls (sorry for my ignorance on > this). Also it would be good for reference on this proposal... > > On Wed, 13 Sep 2017 at 18:40 Boris Zbarsky <[email protected]> wrote: > >> On 9/13/17 9:05 AM, Naveen Chawla wrote: >> > Can someone remind me of the problem doing it this way, if any? >> >> You mean apart from all the existing footguns ASI has? >> >> -Boris >> _______________________________________________ >> es-discuss mailing list >> [email protected] >> https://mail.mozilla.org/listinfo/es-discuss >> > > _______________________________________________ > es-discuss mailing list > [email protected] > https://mail.mozilla.org/listinfo/es-discuss > > -- Jeremy Martin 661.312.3853 @jmar777 <https://twitter.com/jmar777> / @j <https://stream.live/j>
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