Elizabeth Mattijsen
and 1 contributors


PerlIO::via::Rotate - PerlIO layer for encoding using rotational deviation


 use PerlIO::via::Rotate;                 # assume rot13 only
 use PerlIO::via::Rotate 17;              # only a single rotation
 use PerlIO::via::Rotate qw( 13 14 15 );  # list rotations (rotxx) to be used
 use PerlIO::via::Rotate ':all';          # allow for all rotations 0..26

 open( my $in, '<:via(rot13)', 'file.rotated' )
   or die "Can't open file.rotated for reading: $!\n";
 open( my $out, '>:via(rot14)', 'file.rotated' )
   or die "Can't open file.rotated for writing: $!\n";


This documentation describes version 0.08.


This module implements a PerlIO layer that works on files encoded using rotational deviation. This is a simple manner of encoding in which pure alphabetical letters (a-z and A-Z) are moved up a number of places in the alphabet.

The default rotation is "13". Commonly this type of encoding is referred to as "rot13" encoding. However, any rotation between 0 and 26 inclusive are allowed (albeit that rotation 0 and 26 don't change anything). You can specify the rotations you would like to use as strings in the -use- statement

The special keyword ":all" can be specified in the -use- statement to indicate that all rotations between 0 and 26 inclusive should be allowed.




This module is special insofar it serves as a front-end for 27 modules that are named "PerlIO::via::rot0" through "PerlIO::via::rot26" that are eval'd as appropriate when the module is -use-d. The reason for this approach is that it is currently impossible to pass parameters to a PerlIO layer when opening a file. The name of the module is the implicit parameter being passed to the PerlIO::via::Rotate module.


PerlIO::via, PerlIO::via::Base64, PerlIO::via::MD5, PerlIO::via::QuotedPrint, PerlIO::via::StripHTML.


Inspired by Crypt::Rot13.pm by Julian Fondren.

Also thanks to Ribasushi for pointing out at the first Niederrhein PM meeting in 10 years, that the module version check is done by UNIVERSAL::VERSION, and that you can bypass this by providing your own VERSION class method.


Copyright (C) 2002, 2003, 2004, 2012 Elizabeth Mattijsen. All rights reserved. This library is free software; you can redistribute it and/or modify it under the same terms as Perl itself.