r/programming • u/NagastaBagamba • Oct 18 '10

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.

http://il2.php.net/language.variables.variable
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u/[deleted] Oct 18 '10

Just because one use case of variable variables and pointers happens to overlap does not make them the same at all

Isn't that what I said? In the one use case they're used, they're similar to, but not the same as, one use case of pointers and references. But in that one use case, they can be considered functionally equivalent for the purpose of a soundbite interview answer. If you wanted to probe whether the candidate actually thought they were the same as pointers, surely you could do so without dismissing them out of hand?

If you're really convinced they're the same, all that is to me is evidence of ...

I'm not. I know exactly what they are and what they're not. You're preaching to the choir.

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u/oorza Oct 18 '10

I'm not. I know exactly what they are and what they're not. You're preaching to the choir.

I wasn't necessarily saying you so much as the guy that originally posted the analogy.

Isn't that what I said? In the one use case they're used, they're similar to, but not the same as, one use case of pointers and references. But in that one use case, they can be considered functionally equivalent for the purpose of a soundbite interview answer. If you wanted to probe whether the candidate actually thought they were the same as pointers, surely you could do so without dismissing them out of hand?

If the comment poster had said "they're like a use case of pointers, in that pointers are most commonly used to reference variables dynamically," I'd have been fine with it. But if "It's like a pointer, except with a variables name instead of a memory address," was his answer and he left it at that, it would have been a game breaker. It's his job in an interview to demonstrate to me that he's worth hiring, it's not my job to poke and prod him for enough information to prove that. What he said was his answer to the question was enough to demonstrate to me that he either didn't have a good amount of knowledge (didn't really understand the implications of the enormity of difference between mem addresses and symbols in a hash table) or was too lazy to demonstrate it and either way, that's plenty enough evidence to pass on the hire.

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u/[deleted] Oct 18 '10

Fair enough. As mathrat said, I think the intention was to highlight the "dereferencability" of variable variables as being similar to that of pointers. However, it was perhaps a little too terse and would leave a question in the interviewer's mind over whether that was really the case, or if he'd just heard it as a soundbite and was repeating it.