Using data passed by reference to a subroutine

[wardy66]

Hello - me again....

Take this example code:

my @array = (1, 2, 3);
pass_array( \@array );

sub pass_array ($) {
my $aref = shift;
$$aref[1]++
}

This should work and add one to element [1] in the array @array.

My question is, how can I write my subs more legibly by being able to do something like

$sub_array[1]++

and get the same result?

Is it something to do with typeglobs?

Some of my subroutines working on passed references are getting pretty ugly with @{ and $$ all over the place!

TIA

 

[mikevh]

I would say $aref->[1]++, using the "->" as the dereferencing operator. You may or may not consider
that more legible. I've never used "$$var". I think I read
in the Camel book that "$$var" is not recommended, though I don't recall why. Knowing that it wasn't recommended was
enough to make me leave it alone -- and I like the arrows.

 

[wardy66]

Thanks, mikevh

I have been using the $$ and the -> depending on what looks nicest

Still, I would rather just use $array[1] in my subroutines but I can't work out how to make it refer to the same data.

 

[justice41]

You are correct that you can do this with typeglobs. You can't 'use strict' though. it doesn't allow for this type of "advanced" referencing. To accomplish this change your posted code to look something like

@array = (1, 2, 3);
&pass_array( \*array );

sub pass_array ($) {
*aref = shift;
$aref[1]++
}

if you are going to use subroutine prototypes then you need to put the subroutine definition before it's called or use the '&mysubroutine' syntax. otherwise Perl can't check the prototype (it will complain about this if warnings are enabled).

jaa