Craig Francis wrote on 02/09/2015 10:06:
On 1 Sep 2015, at 19:17, Rowan Collins <rowan.coll...@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]
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