On 19 July 2013 18:11, Jelle Zijlstra <jelle.zijls...@gmail.com> wrote:
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> 2013/7/19 Peter Cowburn <petercowb...@gmail.com>
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>> On 19 July 2013 17:36, Daniel Lowrey <rdlow...@gmail.com> wrote:
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>> > I have a simple question about the callability of language constructs
>> and
>> > whether or not that's something that might change in the future.
>> Consider:
>> >
>> > var_dump(is_callable('echo')); // bool(false)
>> > var_dump(call_user_func('echo', 'foo')); // E_WARNING
>> > echo('foo'); // foo
>> >
>> > var_dump(is_callable('isset')); // bool(false)
>> > var_dump(isset(1)); // E_ERROR
>> >
>> > Obviously this behavior arises because tokens like `echo` and `isset`
>> are
>> > language constructs and not functions. I can see some potential benefits
>> > for working around this. For example, say I want to filter only the NULL
>> > elements from an array but keep the other "falsy" values. Recognizing
>> > `isset` as callable would allow me to do this:
>> >
>> > var_dump(array_filter([0, FALSE, NULL], 'isset')); // [0, FALSE]
>> >
>>
>> array_filter([…], 'is_null');
>>
>> That would do the opposite of what you want.
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Absolutely (I blame Friday). Still, this is only being suggested because
"isset" just happens to do what is needed in this case? Where to other
language constructs fit into it?
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>> >
>> > Of course, this limitation is trivial to work around with a userland
>> > callback to check for the explicit NULL equivalency, but it would be
>> nice
>> > to avoid the hassle. So my question is ...
>> >
>> > How deeply ingrained into the engine is this behavior? Is there any
>> chance
>> > of language constructs ever passing the tests for callability or is that
>> > just a pipe dream that's not worth the implementation effort?
>> >
>>
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