... two glossaries. One general and computer science ...

I think that a general, CS-ish glossary or reference source is best provided by existing on-line resources like Wikipedia, to which PerlMonks can easily link. See expression, subroutine, function, etc. Perl should stick to documenting Perlish things. (Only Perl can gloss Perl.)

(Note that in Wikipedia, the CS definitions of "subroutine" and "function" are synonymous | discussed in the same article (per LanX here).)