in reply to Humanized lists of numbers
I wrote a regex for Perl 5.6 that does this. It can be modified easily for letters:
japhy -- Perl and Regex Hacker
sub list2range { local $_ = join ',' => @_; s/(\w+)(?:,((??{''.++(my$x=$+)})))+/$1-$+/g; return $_; }
japhy -- Perl and Regex Hacker
In Section
Seekers of Perl Wisdom