| Re: Undefined variable [message #181265 is a reply to message #181258] |
Fri, 26 April 2013 19:30  |
Thomas 'PointedEars'
Messages: 701
Registered: October 2010
Karma:
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Senior Member |
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Denis McMahon wrote:
> On Thu, 25 Apr 2013 22:05:46 +0200, M. Strobel wrote:
>> Am 25.04.2013 20:23, schrieb Denis McMahon:
>>> On Thu, 25 Apr 2013 10:10:24 +0200, M. Strobel wrote:
>>>> I propose a new reading of "PHP Notice: undefined variable...", it
>>>> goes:
>>>>
>>>> Hey, you are using a variable that is not defined. I will put a
>>>> null
>>> ..........................................................^^^^
>>>
>>> *might*
>>>
>>>> into it.
>>>> Because I will make it easy for you.
>>>> If you don't care I won't either.
>>>
>>> + some lines:
>>> I may put some random value there instead.
>>> The double I use now might not be the string I use next.
>>> Or the integer I used last.
>>> […]
> […]
>
> I did wonder about:
>
> "The array of doubles I'm using now might not be the class of kitten
> hugging monkeys I'll use next week or the tuples of solar hydrogen I used
> yesterday."
>
> but that seemed perhaps a little too complex for some of the readers
> here. :)
>
> (although the kitten hugging monkeys may be more intelligent than some of
> those readers too ... and come to that, so might the tuples of solar
> hydrogen)
However, the non-trolling reader will observe that the evaluation value of a
reference to an undefined variable actually *is* NULL, and that type
juggling as it occurs e.g. with the “==” operator or a type-converting test
(as opposed to with “===”) is *well-defined* (albeit perhaps unintuitive to
some), in PHP (and other dynamically typed programming languages).
It is simply false that a replacement value will be chosen randomly.
<http://www.php.net/manual/en/language.variables.basics.php>
<http://www.php.net/manual/en/language.types.type-juggling.php>
PointedEars
--
Sometimes, what you learn is wrong. If those wrong ideas are close to the
root of the knowledge tree you build on a particular subject, pruning the
bad branches can sometimes cause the whole tree to collapse.
-- Mike Duffy in cljs, <news:Xns9FB6521286DB8invalidcom(at)94(dot)75(dot)214(dot)39>
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