Versions(3)

NAME

       Sort::Versions - a perl 5 module for sorting of revision-like numbers

SYNOPSIS

               use Sort::Versions;
               @l = sort { versioncmp($a, $b) } qw( 1.2 1.2.0 1.2a.0 1.2.a 1.a 02.a );

               ...

               use Sort::Versions;
               print 'lower' if versioncmp('1.2', '1.2a') == -1;

               ...

               use Sort::Versions;
               %h = (1 => 'd', 2 => 'c', 3 => 'b', 4 => 'a');
               @h = sort { versioncmp($h{$a}, $h{$b}) } keys %h;

DESCRIPTION

       Sort::Versions allows easy sorting of mixed non-numeric and numeric
       strings, like the 'version numbers' that many shared library systems
       and revision control packages use. This is quite useful if you are try-
       ing to deal with shared libraries. It can also be applied to applica-
       tions that intersperse variable-width numeric fields within text. Other
       applications can undoubtedly be found.

       For an explanation of the algorithm, it's simplest to look at these
       examples:

         1.1   <  1.2
         1.1a  <  1.2
         1.1   <  1.1.1
         1.1   <  1.1a
         1.1.a <  1.1a
         1     <  a
         a     <  b
         1     <  2
         1.1-3 <  1.1-4
         1.1-5 <  1.1.6

       More precisely (but less comprehensibly), the two strings are treated
       as subunits delimited by periods or hyphens. Each subunit can contain
       any number of groups of digits or non-digits. If digit groups are being
       compared on both sides, a numeric comparison is used, otherwise a ASCII
       ordering is used. A group or subgroup with more units will win if all
       comparisons are equal.  A period binds digit groups together more
       tightly than a hyphen.

       Some packages use a different style of version numbering: a simple real
       number written as a decimal. Sort::Versions has limited support for
       this style: when comparing two subunits which are both digit groups, if
       either subunit has a leading zero, then both are treated like digits
       after a decimal point. So for example:

         0002  <  1
         1.06  <  1.5

       This won't always work, because there won't always be a leading zero in
       real-number style version numbers. There is no way for Sort::Versions
       to know which style was intended. But a lot of the time it will do the
       right thing. If you are making up version numbers, the style with (pos-
       sibly) more than one dot is the style to use.

USAGE

       The function "versioncmp()" takes two arguments and compares them like
       "cmp".  With perl 5.6 or later, you can also use this function directly
       in sorting:

           @l = sort versioncmp qw(1.1 1.2 1.0.3);

       The function "versions()" can be used directly as a sort function even
       on perl 5.005 and earlier, but its use is deprecated.

AUTHOR

       Ed Avis <ed@membled.com> and Matt Johnson <mwj99@doc.ic.ac.uk> for
       recent releases; the original author is Kenneth J. Albanowski
       <kjahds@kjahds.com>.  Thanks to Hack Kampbjrn and Slaven Rezic for
       patches and bug reports.

       Copyright (c) 1996, Kenneth J. Albanowski. All rights reserved.  This
       program is free software; you can redistribute it and/or modify it
       under the same terms as Perl itself.

perl v5.8.8                       2003-08-24                       Versions(3)