Re: Re: Allowing is_* functions to accept multiple parameters

2013/9/18 Sean Coates <sean@seancoates.com>: >> i.e. is_null($a, $b, $c) would be the same as is_null($a) && is_null($b) >> && is_null($c) > > Note that this would not be semantically equivalent in this form, even if > is_null() did accept multiple parameters, because of the > short-circuiting with &&: > > <?php > > function are_null() { > foreach (func_get_args() as $a) { > if ($a !== null) { > return false; > } > } > return true; > } > > function destroy_data() { echo "DESTROYING DATA\n"; } > > // old form: short-circuited; data is not destroyed > if (is_null(null) && is_null(false) && is_null(destroy_data())) { > echo "All null.\n"; > } else { > echo "Not null.\n"; > } > > echo "----\n"; > > // proposed form: no short-circuit; parameters are evaluated at call time and data is destroyed > if (are_null(null, false, destroy_data())) { > echo "Still null.\n"; > } else { > echo "Still not null.\n"; > } > Not a good idea IMHO: it would complexify the execution a lot, think about: $test = "are_null"; if ($test(null, false, destroy_data())) { echo "Still null.\n"; } else { echo "Still not null.\n"; } Looking at the AST wouldn't be enough to tell what would or wouldn't be short-circuited. It looks fine to have is_* functions working on multiple values as Leigh originally proposed. I also feel that it would mostly be used/useful on variables. People worrying about performance and/or execution of code with short-circuiting can (and should) still rely on "&&".