Hi, > On 3 Apr 2015, at 20:46, Dmitry Stogov <dmi...@zend.com> wrote: > > May be you'll also suggest something regarding bitwise shifts with negative > offset? > Allowing negative offsets using opposite directions would fix inconsistency, > but I remember, you didn't like it. > May be keep WARNING (Bit shift by negative number) and then perform shift in > another direction? > + disable negative shifts at compile-time.
I don’t think opposite-direction shifts would work well for a few reasons. I don’t believe this is normal behaviour in other languages, for one. Another issue is that << and >> are not actually opposites, they have different behaviour with respect to signs, so there’d be ambiguity as to what $x << -$y means (is it the same as $x >> $y, or does it deal differently with signs?). Negative shifts being used are usually the result of mistakes, as well, so you want to inform the user. The main problem, though, is that we previously did something different if the shift is negative. Having it now produce a warning, means you’ll see error messages when you run existing code. But shifting in the opposite direction might change the behaviour of existing code silently I think the most sensible solution would be to make negative shifts produce an exception, since they’re really an error, an unsupported operation. I made them be a warning + return FALSE just because it matched division. But that’s not ideal and I’d be fine if it was replaced. Thanks. -- Andrea Faulds http://ajf.me/ -- PHP Internals - PHP Runtime Development Mailing List To unsubscribe, visit: http://www.php.net/unsub.php
