Re: PHP 7.1 - Address PHPSadness #28?

François Laupretre wrote on 23/09/2015 00:11:

So, I thought this was going further and further away from the original idea, which was asking for 'an equivalence of isset() which would consider every value, *including* null, as set, because that's what a lot of devs intuitively assume when using isset()'. That's why I reverted to a unique exists() construct, whose scope is exactly the same as isset(). IMHO, that's the best solution, but anybody is free to provide another patch/implementation.

Fair enough, but for what it's worth, I had *deliberately* moved away from that original idea, because I still don't agree it's valid, and we've had nearly a month of discussion in this thread getting to the bottom of what people's actual requirements are. Clearly, people misunderstand what isset() does, but I think an exists() function which mimics it with a slight difference will only add to that confusion - people will say "oh, if only I had PHP 7.1" rather than looking for array_key_exists, for instance. So the purpose of hasitem() was not to be a variant of isset(), but to be a well-defined function which served a specific need that people have. If there are other needs that people have, there can be other functions to serve them. Looking at some of your edge-cases:

- array_key_exists() does not handle objects implementing ArrayAccess,

Sounds like something which could be fixed in array_key_exists, or easily added to hasitem() without all the other baggage.

- property_exists() does not handle 'magic' properties (those controlled by magic methods),

exists() cannot meaningfully handle these either, without an additional magic method; or, it will call __isset(), and return the same value as isset(), which seems a bit pointless.

- isset() handles string offsets.

What useful functionality could exists() have here?

Note: A variable_exists() function accepting a string wouldn't be more powerful, as exists() provides the same feature when using a '$$' variable variable.

OK, that's not exactly intuitive or easy to use though. If you're checking for a variable's existence, you've presumably dynamically created that variable, so you're quite likely to want the argument to variable_exists() to also be dynamic. Again, variable_exists() would be a function which had a well-defined scope, and obvious how to use it. Regards, -- Rowan Collins [IMSoP]