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Hash::Merge::Simple.3pm

NAME

Hash::Merge::Simple - Recursively merge two or more hashes, simply

VERSION

Version 0.04

SYNOPSIS

     use Hash::Merge::Simple qw/merge/;
 
     my $a = { a => 1 };
     my $b = { a => 100, b => 2};
 
     # Merge with righthand hash taking precedence
     my $c = merge $a, $b;
     # $c is { a => 100, b => 2 } ... Note: a => 100 has overridden => 1
 
     # Also, merge will take care to recursively merge any subordinate hashes found
     my $a = { a => 1, c => 3, d => { i => 2 }, r => {} };
     my $b = { b => 2, a => 100, d => { l => 4 } };
     my $c = merge $a, $b;
     # $c is { a => 100, b => 2, c => 3, d => { i => 2, l => 4 }, r => {} }
 
     # You can also merge more than two hashes at the same time 
     # The precedence increases from left to right (the rightmost has the most precedence)
     my $everything = merge $this, $that, $mine, $yours, $kitchen_sink, ...;
 
 

DESCRIPTION

Hash::Merge::Simple will recursively merge two or more hashes and return the result as a new hash reference. The merge function will descend and merge hashes that exist under the same node in both the left and right hash, but doesn't attempt to combine arrays, objects, scalars, or anything else. The rightmost hash also takes precedence, replacing whatever was in the left hash if a conflict occurs.

This code was pretty much taken straight from Catalyst::Utils, and modified to handle more than 2 hashes at the same time.

EXPORTS

merge

See below.

METHODS

Hash::Merge::Simple->merge( <hash1>, <hash2>, <hash3>, ..., <hashN> )

Hash::Merge::Simple::merge( <hash1>, <hash2>, <hash3>, ..., <hashN> )

Merge <hash1> through <hashN>, with the nth-most (rightmost) hash taking precedence.

Returns a new hash reference representing the merge.

NOTE: The code does not currently check for cycles, so infinite loops are possible:

     my $a = {};
     $a->{b} = $a;
     merge $a, $a;
 
 

NOTE: If you want to avoid giving/receiving side effects with the merged result, use "clone_merge" or "dclone_merge" An example of this problem (thanks Uri):

     my $left = { a => { b => 2 } } ;
     my $right = { c => 4 } ;
 
     my $result = merge( $left, $right ) ;
 
     $left->{a}{b} = 3 ;
     $left->{a}{d} = 5 ;
 
     # $result->{a}{b} == 3 !
     # $result->{a}{d} == 5 !
 
 

Hash::Merge::Simple->clone_merge( <hash1>, <hash2>, <hash3>, ..., <hashN> )

Hash::Merge::Simple::clone_merge( <hash1>, <hash2>, <hash3>, ..., <hashN> )

Perform a merge, clone the merge, and return the result

This is useful in cases where you need to ensure that the result can be tweaked without fear of giving/receiving any side effects

This method will use Clone to do the cloning

Hash::Merge::Simple->dclone_merge( <hash1>, <hash2>, <hash3>, ..., <hashN> )

Hash::Merge::Simple::dclone_merge( <hash1>, <hash2>, <hash3>, ..., <hashN> )

Perform a merge, clone the merge, and return the result

This is useful in cases where you need to ensure that the result can be tweaked without fear of giving/receiving any side effects

This method will use Storable (dclone) to do the cloning

AUTHOR

Robert Krimen, "<rkrimen at cpan.org>"

SEE ALSO

Hash::Merge, Catalyst::Utils

BUGS

Please report any bugs or feature requests to "bug-hash-merge-simple at rt.cpan.org", or through the web interface at http://rt.cpan.org/NoAuth/ReportBug.html?Queue=Hash-Merge-Simple <http://rt.cpan.org/NoAuth/ReportBug.html?Queue=Hash-Merge-Simple>. I will be notified, and then you'll automatically be notified of progress on your bug as I make changes.

SUPPORT

You can find documentation for this module with the perldoc command.

     perldoc Hash::Merge::Simple
 
 

You can also look for information at:

*

RT: CPAN's request tracker

http://rt.cpan.org/NoAuth/Bugs.html?Dist=Hash-Merge-Simple <http://rt.cpan.org/NoAuth/Bugs.html?Dist=Hash-Merge-Simple>

*

AnnoCPAN: Annotated CPAN documentation

http://annocpan.org/dist/Hash-Merge-Simple <http://annocpan.org/dist/Hash-Merge-Simple>

*

CPAN Ratings

http://cpanratings.perl.org/d/Hash-Merge-Simple <http://cpanratings.perl.org/d/Hash-Merge-Simple>

*

Search CPAN

http://search.cpan.org/dist/Hash-Merge-Simple <http://search.cpan.org/dist/Hash-Merge-Simple>

ACKNOWLEDGEMENTS

This code was pretty much taken directly from Catalyst::Utils:

Sebastian Riedel "sri@cpan.org"

Yuval Kogman "nothingmuch@woobling.org"

COPYRIGHT & LICENSE

Copyright 2008 Robert Krimen, all rights reserved.

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