On Oct 8, 2012, at 10:04 AM, Andreas Rossberg wrote: > On 8 October 2012 18:24, Allen Wirfs-Brock <[email protected]> wrote: >> You desugaring would break ES<=5.1 compatibility for: >> >> (function (p) { >> var p; >> return typeof p >> })("test") >> >> ES5.1 returns "string", your desugaring returns "undefined" > > I'm probably just being blind, but I'm not seeing it. Why? > > /Andreas > In ES <= 5.1, function declarations over-write formal parameters. But var declarations, without initializer do not assign undefined to already local bindings (including formal parameters) that already exist.
You desugaring would create a new var declaration in a new scope contours that would be initialized to undefined and shadow the like-named formal parameter. Allen _______________________________________________ es-discuss mailing list [email protected] https://mail.mozilla.org/listinfo/es-discuss
