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Comment by chromatic | Hacker News Reader

I'd say it's more a like a pointer than not.

Are you familiar with the distinction between "pass by reference" and "pass by value"? If you call everything which behaves in the former way a pointer, I think you confuse an implementation strategy with a language construct and you lose an important feature of C pointers.

What you see in Perl (and Ruby) is a unique identifier that happens to be a memory address. It could be anything else, but the memory address is an identifier that's essentially free to generate. That's it. It's otherwise irrelevant. You have to write code in a language which has pointers to do anything with that information, and even then you have to cast it to a real pointer to do so.

We could discuss Perl 5's dereferencing syntax (it's ugly, no argument there) but that's a syntax issue and not an implementation concern.

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I'm familiar with C and understand why pointers are there. I understand what you are saying and you make a fair point. I'll take back my statement Perl has pointers. Claiming Perl has pointers is very murky (although it has some truth to it). The heart of what bothers me is you have to deference addresses (similar to what happens with pointers in C) in Perl. This shouldn't exist in a scripting language syntax. It lots of unnecessary syntax, compile errors, and mental hoops you have to go through when coding. Ruby and Python don't have this serious (I think so at least) wart.

> Are you familiar with the distinction between "pass by reference" and "pass by value"? If you call everything which behaves in the former way a pointer, I think you confuse an implementation strategy with a language construct and you lose an important feature of C pointers.

The heart of what bothers me is you have to deference addresses...

I don't understand why you keep saying that. They're not addresses.

From the language side of things, they're first class scalar entities just like strings and numbers. From Perl 5 they have nothing to do with memory addresses. (You might as well suggest that a nested data structure in any language without pointers is "dereferencing addresses", or that accessing object attributes is "dereferencing addresses".)

You can't write in Perl something like:

    my $reference = 'ARRAY(0x1234abcd)';

... and expect to access the array at that point in memory even if you stringified an array reference and saw that its stringification included that hex address. References are not pointers. They don't dereference addresses.

From the internals side, they're SVs, just like all other scalars in Perl 5. An SV is a C structure. Yes, the internals use pointers, but so does any other virtual machine implementation.

(Okay, you can write code like I said above, but to make that work correctly, you have to write C to do it, because C allows direct access to memory by address.)

I'm sorry. I'm actually a little dyslexic and if a wrong word slips by the spell check I can get myself in trouble. s/deference/dereference/.

Consider: my $x = [1,2,3]; print "@$x\n";

In the second line I consider "$" dereferencing the "address" that points to an array. I don't know anything about the internals of Perl virtual machine and what that "address" really means. But to the common programmer it seems like you have to do the same work you would have do in C dereferencing pointers. Python and Ruby have no such operator, right? This unnecessary work is what I'm complaining about (and all the associated extra syntax).

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