On 13 May 2011 01:50, Mark S. Miller <[email protected]> wrote: >> Assume that >> >> - we distinguish two variants of the eval function, strict and >> non-strict -- let's call these values EVAL_s and EVAL_ns. >> - initially (in global scope), the identifier `eval' is bound to EVAL_ns. >> - in a strict mode scope it will be considered rebound to EVAL_s >> instead (unless it has already been shadowed by user code anyway). >> >> (In addition, at least in strict mode, the only calls to `eval' that >> are considered _direct_ calls would be those where `eval' statically >> refers to the initial binding or one of the implicit strict-mode >> rebindings -- i.e., where it has not been shadowed by the user.) > > I think the core insight here is good, and had it been made in time, could > have led to a better semantics than what we adopted into ES5. I like the > idea that ' "use strict";' effectively inserts a > DeclarativeEnvironmentRecord binding 'eval' to EVAL_s, though I'd put this > record on the stack at the strict/non-strict boundary rather than just above > the global object.
Yes, my previous description of "shadowing" `eval' at the point of "use strict" was meant to describe just that. > Even better, since 'eval' cannot be rebound by ES5/strict, ES-next, or SES > code, and since "eval(str)" is effectively a special form anyway, why not > remove the dynamic "and if 'eval' is bound to the original global eval > function" condition from direct eval? Why not just treat "eval(str)" as a > direct eval special form independent of what 'eval' is bound to in that > scope? That's what I tried to suggest in the parenthesized paragraph above, and it was the reason for my question to Allan. The difficulty in ES5 would be that scoping is not really static -- not even in strict-mode code, which might still be surrounded by non-script scopes shadowing `eval' dynamically (esp `with'). But for Harmony it'd be nice. Thanks, /Andreas _______________________________________________ es-discuss mailing list [email protected] https://mail.mozilla.org/listinfo/es-discuss
