array copy question

[smackdab]

In 5.6 I was doing this to copy an array from an array ref:

my @$ra_ret_save = @$ra_ret;

5.8 doesn't like it and now I am doing:

my $ra_ret_save;
@{$ra_ret_save} = @{$ra_ret};

Was the orig wrong, what changed?

[duff]

I don't think you are remembering the 5.6 code correctly. Most likely you had my @array = @{$array_ref};. If my @$foo did work with 5.6 is was a bug and what changed was that bug was fixed.

[Roy Johnson]

Just to be clear: the curlies are still not required, but you have to declare the reference ($ra_ret_save) separately from dereferencing it.

my $ra_ret_save;
@$ra_ret_save = @$ra_ret;

If you really had a jones for doing it all at once:

my $ra_ret_save = [@$ra_ret];

[Roger]

Yes declaration of array reference has changed in 5.8. The code below will not compile under 5.8:


my @$ra_ret_save = @$ra_ret;

You do not have to declare array refence and copy from another array in two separate steps. You can do in one single step -


my $ra_ret_save = [ @$ra_ret ];

I have created a demo script below -


use strict;
use warnings;
use Data::Dumper;

my $ra_ret = [ qw/ a b c d / ];
print Dumper($ra_ret);

my $ra_ret_save = [ @$ra_ret ];
print Dumper($ra_ret_save);

And the output when run from 5.8 and 5.6 -


perl 5.8.0
----------
$VAR1 = [
          'a',
          'b',
          'c',
          'd'
        ];
$VAR1 = [
          'a',
          'b',
          'c',
          'd'
        ];

perl 5.6.1
----------
$VAR1 = [
          'a',
          'b',
          'c',
          'd'
        ];
$VAR1 = [
          'a',
          'b',
          'c',
          'd'
        ];