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hash::withdefaults(3pm) [debian man page]

Hash::WithDefaults(3pm) 				User Contributed Perl Documentation				   Hash::WithDefaults(3pm)

NAME

       Hash::WithDefaults - class for hashes with key-casing requirements supporting defaults

       version 0.05

SYNOPSIS

	 use Hash::WithDefaults;

	 %main = ( ... );
	 tie %h1, 'Hash::WithDefaults', {...};
	 tied(%h1)->AddDefault(\%main);
	 tie %h2, 'Hash::WithDefaults', [...];
	 tied(%h2)->AddDefault(\%main);

	 # now if you use $h1{$key}, the value is looked up first
	 # in %h1, then in %main.

DESCRIPTION

       This module implements hashes that support "defaults". That is you may specify several more hashes in which the data will be looked up in
       case it is not found in the current hash.

   Object creation
	       tie %hash, 'Hash::WithDefault', [$case_option], [\%values];
	       tie %hash, 'Hash::WithDefault', [$case_option], [@values];
	       tie %hash, 'Hash::WithDefault', [$case_option], [%values];

       The optional $case_option may be one of these values:

	 Sensitive     - the hash will be case sensitive
	 Tolower       - the hash will be case sensitive, all keys are made lowercase
	 Toupper       - the hash will be case sensitive, all keys are made uppercase
	 Preserve      - the hash will be case insensitive, the case is preserved
	 Lower - the hash will be case insensitive, all keys are made lowercase
	 Upper - the hash will be case insensitive, all keys are made uppercase

       If you pass a hash or array reference or an even list of keys and values to the tie() function, those keys and values will be COPIED to the
       resulting magical hash!

       After you tie() the hash, you use it just like any other hash.

   Functions
       AddDefault

	       tied(%hash)->AddDefault(\%defaults);

       This instructs the object to include the %defaults in the search for values.  After this the value will be looked up first in %hash itself
       and then in %defaults.

       You may keep modifying the %defaults and your changes WILL be visible through %hash!

       You may add as many defaults to one Hash::WithDefaults object as you like, they will be searched in the order you add them.

       If you delete a key from the tied hash, it's only deleted from the list of specific keys, the defaults are never modified through the tied
       hash. This means that you may get a default value for a key after you deletethe key from the tied hash!

       GetDefaults

	       $defaults = tied(%hash)->GetDefaults();
	       push @$defaults, \%another_default;

       Returns a reference to the array that stores the defaults.  You may delete or insert hash references into the array, but make sure you
       NEVER EVER insert anything else than a hash reference into the array!

   Config::IniHash example
	 use Config::IniHash;
	 $config = ReadIni $inifile, withdefaults => 1, case => 'preserve';

	 if (exists $config->{':default'}) {
	   my $default = $config->{':default'};
	   foreach my $section (keys %$config) {
	     next if $section =~ /^:/;
		 tied(%{$config->{$section}})->AddDefault($default)
	   }
	 }

       And now all normal sections will get the default values from [:default] section ;-)

AUTHOR

       Jan Krynicky <Jenda@Krynicky.cz> http://Jenda.Krynicky.cz

COPYRIGHT

       Copyright (c) 2002-2009 Jan Krynicky <Jenda@Krynicky.cz>. All rights reserved.

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

perl v5.14.2							    2012-05-26						   Hash::WithDefaults(3pm)

Check Out this Related Man Page

Tie::Hash::Regex(3pm)					User Contributed Perl Documentation				     Tie::Hash::Regex(3pm)

NAME

       Tie::Hash::Regex - Match hash keys using Regular Expressions

SYNOPSIS

	 use Tie::Hash::Regex;
	 my %h;

	 tie %h, 'Tie::Hash::Regex';

	 $h{key}   = 'value';
	 $h{key2}  = 'another value';
	 $h{stuff} = 'something else';

	 print $h{key};  # prints 'value'
	 print $h{2};	 # prints 'another value'
	 print $h{'^s'}; # prints 'something else'

	 print tied(%h)->FETCH(k); # prints 'value' and 'another value'

	 delete $h{k};	 # deletes $h{key} and $h{key2};

       or (new! improved!)

	 my $h : Regex;

DESCRIPTION

       Someone asked on Perlmonks if a hash could do fuzzy matches on keys - this is the result.

       If there's no exact match on the key that you pass to the hash, then the key is treated as a regex and the first matching key is returned.
       You can force it to leap straight into the regex checking by passing a qr'ed regex into the hash like this:

	 my $val = $h{qr/key/};

       "exists" and "delete" also do regex matching. In the case of "delete" all vlaues matching your regex key will be deleted from the hash.

       One slightly strange thing. Obviously if you give a hash a regex key, then it's possible that more than one key will match (consider
       c<$h{qw/./}>).  It might be nice to be able to do stuff like:

	 my @vals = $h{$pat};

       to get all matching values back. Unfortuately, Perl knows that a given hash key can only ever return one value and so forces scalar context
       on the "FETCH" call when using the tied interface. You can get round this using the slightly less readable:

	 my @vals = tied(%h)->FETCH($pat);

   ATTRIBUTE INTERFACE
       From version 0.06, you can use attributes to define your hash as being tied to Tie::Hash::Regex. You'll need to install the module
       Attribute::Handlers.

METHODS

   FETCH
       Get a value from the hash. If there isn't an exact match try a regex match.

   EXISTS
       See if a key exists in the hash. If there isn't an exact match try a regex match.

   DELETE
       Delete a key from the hash. If there isn't an exact match try a regex match.

AUTHOR

       Dave Cross <dave@mag-sol.com>

       Thanks to the Perlmonks <http://www.perlmonks.org> for the original idea and to Jeff "japhy" Pinyan for some useful code suggestions.

COPYRIGHT

       Copyright (C) 2001-8, Magnum Solutions Ltd.  All Rights Reserved.

LICENSE

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

SEE ALSO

       perl(1).

       perltie(1).

       Tie::RegexpHash(1)

perl v5.10.0							    2008-06-30						     Tie::Hash::Regex(3pm)
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