Mark, could you explain how the condition and iteration statements in the for loop interact with such an initialization? I agree that banning these seems like the clearer way to go.
On Thu, Jun 5, 2014 at 10:17 AM, Mark S. Miller <[email protected]> wrote: > Why not accept these as for-loop initializations, so that x actually has > that function and that class as its initial value in the first iteration of > the loop? To me, that's the least surprise. Since this is a position in > which some declarations are accepted, anything there that looks like a > declaration should be a declaration. > > However, I agree that banning these is much less surprising than allowing > them as expressions rather than declarations. > > > > On Thu, Jun 5, 2014 at 7:58 AM, Andreas Rossberg <[email protected]> > wrote: > >> C-style for-loops allow declarations as init statements, but only some >> of them. Yet, the others (function and class) are actually >> syntactically legal in that position as well, because they are simply >> parsed as expressions. Consider: >> >> let x = 0 >> for (let x = 1; ;) x // 1 >> for (const x = 1; ;) x // 1 >> for (function x(){}; ;) x // 0 >> for (class x(){}; ;) x // 0 >> >> I think these latter two examples violate the principle of least >> surprise. I wonder if it wouldn't be cleaner to rule them out, by >> imposing the same lookahead restrictions on for-loop init expressions >> as there are for expression statements. >> >> The one caveat is that for function, that would actually be a breaking >> change, but is it likely to be a real world one? >> >> What do you think? >> >> /Andreas >> _______________________________________________ >> es-discuss mailing list >> [email protected] >> https://mail.mozilla.org/listinfo/es-discuss >> > > > > -- > Cheers, > --MarkM > > _______________________________________________ > es-discuss mailing list > [email protected] > https://mail.mozilla.org/listinfo/es-discuss > >
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