Dan Kogai > Attribute-Constant > Data::Lock

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Module Version: 0.04   Source  

NAME ^

Data::Lock - makes variables (im)?mutable

VERSION ^

$Id: Lock.pm,v 0.4 2013/03/20 22:17:40 dankogai Exp dankogai $

SYNOPSIS ^

   use Data::Lock qw/dlock dunlock/;

   # note parentheses and equal

   dlock( my $sv = $initial_value );
   dlock( my $ar = [@values] );
   dlock( my $hr = { key => value, key => value, ... } );
   dunlock $sv;
   dunlock $ar; dunlock \@av;
   dunlock $hr; dunlock \%hv;

DESCRIPTION ^

dlock makes the specified variable immutable like Readonly. Unlike Readonly which implements immutability via tie, dlock makes use of the internal flag of perl SV so it imposes almost no penalty.

Like Readonly, dlock locks not only the variable itself but also elements therein.

As of verion 0.03, you can dlock objects as well. Below is an example constructor that returns an immutable object:

  sub new {
      my $pkg = shift; 
      my $self = { @_ };
      bless $self, $pkg;
      dlock($self);
      $self;
  }

Or consider using Moose.

EXPORT ^

Like List::Util and Scalar::Util, functions are exported only explicitly. This module comes with dlock and dunlock.

  use Data::Lock;                   # nothing imported;
  use Data::Lock qw/dlock dunlock/; # imports dlock() and dunlock()

FUNCTIONS ^

dlock

  dlock($scalar);

Locks $scalar and if $scalar is a reference, recursively locks referents.

dunlock

Does the opposite of dlock.

SEE ALSO ^

Readonly, perlguts, perlapi

AUTHOR ^

Dan Kogai, <dankogai+gmail at gmail.com>

BUGS & SUPPORT ^

See Attribute::Constant.

COPYRIGHT & LICENSE ^

Copyright 2008 Dan Kogai, all rights reserved.

This program is free software; you can redistribute it and/or modify it under the same terms as Perl itself.

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