On 1 October 2014 16:09, Erik Arvidsson <[email protected]> wrote: > The static error is problematic. I'm pretty sure that engines that do lazy > parsing of functions is not going to report static errors before doing a > full parse of the function.
Well, it is no harder than reporting reference errors for unbound variables in strict mode, which is already required for ES5. ...However, at least V8 does not report that correctly either, as soon as lazy parsing kicks in. On 1 October 2014 17:39, Mark S. Miller <[email protected]> wrote: > So the question is not "Can this early error be reported accurately without > parsing?", since essentially none can, so no engines postpone parsing. The > question is whether a particular new early error would require these > lightweight early parsers to do something that they can't do while > preserving their current efficiency. > > Statically apparent assignment to const variables does not seem like a > burden. This analysis (as well as diagnosing unbound variables in strict mode) requires more than just parsing -- it requires full binding analysis. You have to construct all scope environments, analyse all declarations, and track all variable uses, even during "lazy" parsing. That has non-trivial complexity (although I don't know how costly it is). /Andreas _______________________________________________ es-discuss mailing list [email protected] https://mail.mozilla.org/listinfo/es-discuss
