Re: PHP 7.1 - Address PHPSadness #28?

Craig Francis wrote on 02/09/2015 10:06:

On 1 Sep 2015, at 19:17, Rowan Collins <rowan.collins@gmail.com> wrote:

I'm still not sure how exists() would be anything other than an alias for array_key_exists().

I think that is the case as well (ish). But considering that isset() seems to be the function that is used most of the time, I want to consider why that is the case. Before last week, if someone asked me to write some code to see if a variable (or key) exists,

Again, you insist on drawing a false equivalence to the different concepts of variable and array key. This makes the following sentence really easy to dismiss:

I would have simply used isset() without thinking (this being a problem if the variable was set to NULL).

No, it wouldn't be a problem if a VARIABLE was set to null, because there is no practical difference between an unset variable and one set to null, so you never need to ask which you have. It *would* be a problem if you were testing for the existence of an array key. There should probably be a prominent link to array_key_exists() and property_exists() on the isset() manual page

The second one does also represent the variable in a different way (grep for "$_GET['q']", where it only appears 3 times in that code).

This is a more reasonable point, and I was pondering whether it would be possible to allow a more natural syntax. It would probably require a lot of "magic" in the engine, though, because it would have to parse exists($foo['bar']['baz']) in some special way to know that it needed to first find the value of $foo['bar'], and then do an existence check for key 'baz', rather than just treating the whole thing as an expression to resolve before exists() was called. Evaluating things like exists(foo()[ bar() ]) correctly might get messy, as would giving a meaningful result or error if you wrote exists($foo['bar'] + 1).

And the second one does not really check for the existence of $_GET, which in this case is probably ok.

I'm not really sure what you mean by this. In summary, I don't think any language change is needed here, but documentation needs to be improved. I will have a go at drafting a new intro for the isset() page when/if I get time. Regards, -- Rowan Collins [IMSoP]