On Jan 9, 2012, at 9:28 AM, Andreas Rossberg wrote: > On 9 January 2012 16:54, Brendan Eich <[email protected]> wrote: >> The question is how bad these will be for anyone writing JS naively, based >> on current and emerging (ES6) docs, without explicit opt-in. >> >> The answer entails at least: >> >> 1. ES5-strict semantic changes, e.g. arguments aliasing, without early >> errors. >> >> 2. Completion reform. >> >> 3. New early errors. >> >> I think 3 is a good thing and a non-problem. Some of us hope 2 is a matter >> of indifference to real-world code, but we don't know for sure. That leaves >> 1. > > Yes, but (1) is not a trivial set -- e.g. receiver coercions, eval > semantics, delete type errors, arguments aliasing, poisoning of > caller/arguments, etc.
You're right, there's a lot of runtime meaning shift in ES5-strict, indeed -- more than just parameter no-aliasing. Still the bet we are trying to place (not done yet detailing the proposal) is that most people won't use explicit version-based opt-in (also, such noise gets lost easily over the life of code snippets), *and* that the hard cases you cite are rare. None is common. /be _______________________________________________ es-discuss mailing list [email protected] https://mail.mozilla.org/listinfo/es-discuss
