Re: Re: Re: Re: NEWBIE Brain Teaser

[merlyn]

Explicit referencing requires an explicit dereference. Aliasing is intended to mean something much more transparent.

-- Randal L. Schwartz, Perl hacker

[Ri-Del]

Alright, then in learning from this brain teaser not only have I learned the original point, but also stumbled upon another concept that I need to read up on. Thank you!

I take it then that aliasing was meant to make our lives easier both in how we code as well as in how we think about the whole process?

[tilly]

Yes, that is what aliasing is supposed to do.

For instance consider this:

# No aliasing...
foreach my $thing (@array) {
  # $thing is now an *alias* for something in @array
  # In reality there is a layer of indirection here
  # from the concept of $thing to the array, but you
  # do not have to write the dereferencing since Perl
  # hid it for you in $thing

  # ...
}
# Alias over

See? There is indirection needed to do what happens in that loop, but you don't have to think about it, and it does not appear as explicit dereferences in your code. It just works.

That is the difference between an alias and a reference. With a reference the indirection shows up as your having to tell Perl to dereference things. With an alias it is hidden inside the definition of the variable.

That is an amusing difference between Perl and, say, C. The same code written in C is in reality more direct than in Perl. But the Perl code *looks* more direct because you don't see the indirections...

[Ri-Del]

That is really cool! Thanks for explaining it.