Richard A. O'Keefe wrote:
The mutablity of r here really isn't a problem. Nor is the mutability of variables _as such_ really the problem in the PHP proposal. The problem is that it's the *same* variable every time. If PHP loops introduced new bindings on every iteration, this particular problem would not exist.
Well, arguably it's not only the loop variable that can be susceptible to this problem. There could be other variables in the loop body which change each time through (e.g. while loops). Consider this pseudo-code (sorry, my PHP is a bit rusty, this syntax is C really) char c; while (!eof(fp)) { c = getChar(fp); bind_event(... some lambda expression referencing c ...); } It's pretty surprising to the programmer if all that family of lambda expressions reference the *variable* c (and hence, in practice, its final value) rather than the *value* c. Well, maybe that doesn't surprise everyone. It surprised me the first time I used closures in Javascript and judging by a few google searches I wasn't alone in that. Jules