On Thu, 14 Apr 2011 02:24:56 +0200, Ben Schmidt
<mail_ben_schm...@yahoo.com.au> wrote:
I think these shortcuts could be really useful for array elements, but
for other variables I am really sceptical and I think they would do
more harm than good. Generally I do not really see any reason why a
variable should not be 'instanciated' before use.
So
+1 if this shortcut is implemented to only work for array elements.
-1 for any other variable type.
There are two issues here.
1. Suppression of notice. I agree, it is best done only for array
keys. It's not hard to initialise a variable with $var=null at the
beginning of a code block to avoid such a notice, and that is the
appropriate way to do it for variables.
2. Offering a shortcut for the common idiom isset($x) ? $x : $y in
line with the DRY design principle. A notice would never be emitted
here in any case. The problem is that this idiom is still in wide use
despite the shortcut ternary operator already provided, because an
isset() check is different to a boolean cast.
Some thoughts:
- The actual intent of 2. is probably $x!==null ? $x : $y i.e. it's
not about suppressing notices at all, but about offering a default
value, and the idiom quite probably only uses isset() because it
predated null in the language.
I have never felt the need for a shortcut in these cases. It would be
interesting to see some code where this would be practical.
- If we view 2. in this way, the two problems are independent, and it
seems to me it would be best to solve them independently, rather
than with a single operator.
So, I suggest:
1. An array lookup mechanism that suppresses the notice for undefined
keys. It would work the same as regular array index lookups except
that the notice for undefined keys (and only for undefined keys)
would not be generated (it would not just be hidden, but would never
be even generated).
This is what I feel PHP is missing. Particularly when it comes to
multi-dimensional arrays. Because this feature is missing I tend to do
something like
function generateHash($x, $y, $z)
{
return "$x::$y::$z";
}
if (isset($a[generateHash($x, $y, $z)]) {
...
}
instead of
if (isset($a[$x]) && isset($a[$x][$y]) && isset($a[$x][$y][$z])) {
...
}
Arguing about syntax is then a second step. However, my views on this
are:
I think it best to avoid discussing the actual syntax before agreeing on
what we really need.
--
Ole Markus With
Systems Architect - Sportradar AS
Developer - Gentoo Linux
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