Re: Arrow dereference operator question

On 5/31/07, David Unric <dunric29a@xxxxxxxxx> wrote:
Based on perlref documentation arrow operator between brackets subscripts
may be omitted so the following code is valid:

@array = ( [1, 2], [3, 4] );
$element = $array[0][0]; # shorthand for $element = $array[0]->[0]


Could somebody explain why it causes syntax error when the above rule is
applied to returned value of a subroutine ?

sub mysub {
@array = ( [1, 2], [3, 4] );

return @array;
}

$element = (&mysub)[0][0]; # $elem = (&mysub)[0]->[0] is valid
------------------------------
syntax error at testarr.pl line 7, near "]["


My best guess is that the problem here is that (mysub())* is a list
not an array. Lists are not multidimensional. Try

my $element = ([1, 2], [3, 4])[0][0];

Notice how it gets the same error?

The simple solution is to use the arrow, or have the sub return an
arrayref. Here are some ways to do it:

#!/usr/bin/perl

use strict;
use warnings;

sub list {
my @array = ( [1, 2], [3, 4] );
return @array;
}

sub aref {
my @array = ( [1, 2], [3, 4] );
return \@array;
}

print (
(list())[0]->[0], "\n",
"${[list()]}[0][1]\n",
"${aref()}[1][0]\n",
(aref())->[1][1], "\n"
);



* don't use &mysub unless you know why you are doing it, use mysub() instead
.

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