[Dancer-users] Changing config hashref directly (was: Re: Dancer::layout has been deprecated)

Aaron Crane perl at aaroncrane.co.uk
Mon May 23 11:20:13 CEST 2011

damien krotkine <dkrotkine at gmail.com> wrote:
> That can be a good idea, but we should be extremely cautious with ties :
> they are slow, and a bit magic.

Another possibility would be to use lock_hash() from Hash::Util (core
since Perl 5.8.0); that forbids modification of the hash, but in a way
that doesn't affect lookup speed.  The only downside is that you can
still modify arrays and hashes that are stored (by reference) in the

use Hash::Util qw<lock_hash>;
my %hash = (array => [], hash => {}, string => 'foo');

push @{ $hash{array} }, 1;  # allowed
$hash{hash}{nested}++;      # allowed

$hash{string} = 1;          # forbidden (replaces a stored value)
$hash{new_key} = 1;         # forbidden (adds a key)
delete $hash{array};        # forbidden (deletes a key)

Aaron Crane ** http://aaroncrane.co.uk/

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