How is this different from (bool) $var?

It isn't, but this is usable as callback.

@laruence That's not the same thing. For instance, it will fail if you pass an array, while convert_to_boolean works with any variable. @Jille 's implementation seems correct to me, though he could use convert_to_boolean_ex to avoid a separation if it's not necessary.

I accidentally also committed the convert_to_boolean -> convert_to_boolean_ex in the previous commit. I'm not sure whether that is the only change required.

@Jille Sorry, disregard that last part of my comment. convert_to_boolean_ex is not a good idea here (more cycles, though it would still work), because it precedes a copy anyway. Since return_value is only a zval * and not zval **, that copy is necessary.

With anon functions, I'm not sure why function($x) { return (bool)$x;} doesn't really solve this use case.

Most of all it's a consistency improvement. We have strval, doubleval, floatval and intval so one would assume boolval also exists.

Should this be discussed on the internals list? Should I open a bug and hope someone will merge it? Should I just wait till someone hits the "Merge" button?

@Jille You should bring this up on internals. It adds a new function, so it can't be simply merged. Also it's debatable whether we really need it, so... writing a mail to internals should be the right thing to do :)

It makes sense to add it to 5.5

Add a test please and I will pull it. Also squash 90a3d47 and a5d113e together (if not I can do that myself)

74b4ef5 (in my boolval-branch) contains the function and a test. Thanks!

Merged as 753c336. Thank you for your contribution.

Would be great if you can also help the docteam adding that function to phpdoc :)