Being bored, I re-did
Text::FastSoundex in XS and benchmarked it against
the old perl4-ish
Text::Soundex in the Perl distribution. The benchmark result (18x faster) pleased me a lot.
Alas, shortly before uploading it to the CPAN I realized that I was maybe overly smart since the module exists in version 3.02 on the CPAN and Mark Mielke already XSified it. So in the end there is another module of mine that will remain in my private repository forever and the fact that it's between 8% and 23% faster than the most recent CPAN version. A figure that is pointless but at least tickles my vanity a bit.
PS: And I learnt that one shouldn't write
res = toUPPER(*c++) as this and other macros in handy.h evaluate their argument more than once.