INSTALL : % perl Makefile.PL % make % make test % make install DESCRIPTION : This module lets you layer hashes on top of each other opaquely so that top most layers obscure bottom ones. Think of it like sheets of OHP transparencies, if a value is set in a top and bottom layer then that's you when you access that key you get the value from the top layer but if you access something not set in the top layer but set in the bottom layer then you get the value from the bottom layer ... ... and breath. In short : Tied Hash : foo=>'bob' , quux=>'fleeg' | | ^ | Layer 1 : foo=>'bob' ^ Layer 2 : foo=>'bar' , quux=>'fleeg' So why is this useful. Well, the obvious application is for preferences. In a CGI app you could tie in the bottom most hash to a database with default users' preferences, the second layer with the current user's preferences, the layer above that with the per session preferences and the layer above that with the per request values. AUTHOR : Simon Wistow COPYING : This module is distributed under the same terms as Perl itself