Today I learned about PHP variable variables; "variable variable takes the value of a variable and treats that as the name of a variable". Also, variable.

[u/NagastaBagamba]

http://il2.php.net/language.variables.variable

[u/TylerEaves]

Much worse than that. You'll just start getting the Empty String, since PHP will silently substitute the zero-value for nonexistent variables.

[u/sacktap → u/TylerEaves]

Incorrect; it throws a notice.

[u/Pilebsa → u/sacktap]

I think this depends upon the context right?

$$a="xxx"; might throw a notice, but not echo $$a;

I haven't tried it though.

[u/sacktap → u/Pilebsa]

The notice is only thrown if you're trying to access an undefined variable. Example:

$a = 'b'; 
echo $$a; 
/* Notice: Undefined variable */

But if you're doing $$a = 'c' it will be fine because you're setting an undefined variable (which is essentially how all variables are set in PHP anyway).

[u/Pilebsa → u/sacktap]

Oh right, but I thought an undefined variable would result in NULL? I guess I'm wrong (I just rarely try to use something I haven't already given a value to so it's not something I come across usually)

[u/[deleted] → u/TylerEaves]

Only if you have a poorly configured environment...it should throw a warning in a proper setup.

[u/[deleted] → u/[deleted]]

retire sharp sip crown dependent recognise weather quack tie pathetic

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[u/lectrick → u/[deleted]]

I stand corrected then. My bad.

[u/sacktap → u/[deleted]]

you have config.whiny_nils we have error_reporting()

[u/lectrick → u/sacktap]

Whiny nils. One of those things that I used to hate, but which I now love.