aliasing a hash field

Sixtease has asked for the wisdom of the Perl Monks concerning the following question:

Dear fellows

Can I alias a hash entry to a global variable? I'd like something like this to happen:

our @arr;
my %h;
somehow_alias($h{'key'}, @arr);
$h{'key'}[0,1] = qw(hello world);
print $arr[0], ' ', $arr[1], "\n";
# Desired output:
# hello world
[download]

Now that's the Y part. The X part is that I'm running user-provided subrefs in a module and would like these subs to see some fields that the $self object has without messing with the sub's parameters.

use strict; use warnings; print "Just Another Perl Hacker\n";

Comment on aliasing a hash field Download Code

Replies are listed 'Best First'.
Re: aliasing a hash field by BrowserUk (Patriarch) on Feb 15, 2008 at 18:06 UTC
Like this? `@{ $hash{ key } }[ 0, 1 ] = qw[ hello world ];; *array = $hash{ key };; print "@array";; hello world` [download] Examine what is said, not who speaks -- Silence betokens consent -- Love the truth but pardon error. "Science is about questioning the status quo. Questioning authority". In the absence of evidence, opinion is indistinguishable from prejudice. "Too many [] have been sedated by an oppressive environment of political correctness and risk aversion."	[reply] [d/l]
Re: aliasing a hash field by kyle (Abbot) on Feb 15, 2008 at 16:58 UTC
I don't see a way for `$h{'key'}[0,1]` to be valid syntax regardless. Maybe this is close enough? `use Test::More 'no_plan'; our @arr; my %h; $h{'key'} = \@arr; # take a reference to @arr @{$h{'key'}}[0,1] = qw(hello world); is( $arr[0], 'hello', '$arr[0] is "hello"' ); is( $arr[1], 'world', '$arr[1] is "world"' ); is( $h{'key'}->[0], 'hello', q{$h{'key'}->[0] is 'hello'} );` [download]	[reply] [d/l] [select]
Re: aliasing a hash field by Sixtease (Friar) on Feb 15, 2008 at 20:24 UTC
Yeah, ehm, well, I must have been high on something when I wrote that. :-) `*arr = $h{'key'}` is the obvious solution to Y that should have crossed my mind. `$h{'key'}[0,1]` may not be invalid syntax but it's definitely not what I meant. The solution to X is that I simply make a method to set the things I want to show to the subs instead of adding magic to manipulating the object. My question was totally unclear and I apologize. Seeing that I got helpful and not bashing replies confirms my deep conviction that the Perlmonks community is one of the most mature, tolerant and wonderful communities to ever inhabit the cyberspace. use strict; use warnings; print "Just Another Perl Hacker\n";	[reply] [d/l] [select]