It would have to be finstem, a simple command-line program I wrote to reduce Finnish words down to their root form.
Finnish is a lot like Latin or Russian in that its words
often become lumbering behemoths of rewritten consonants,
suffixes upon suffixes, and this makes it hard to look up
in a dictionary – that is, until you factor in its
very regular orthography and the phenomenal
efforts of the Finnish programming industry: finstem
is
basically a very specialized UI for
the OpenOffice spell checker,
and I have no shame in admitting that.
cloc
puts it at under 200 lines of code altogether,
including the tiny fzf
wrapper I ship with it to let
people stem words as they type them.
I pretty much consider it feature complete by this point. I use the wrapper dozens of times in an average day while studying the language; there were a few bugs early on my dogfooding revealed, but the nice thing about small CLI programs is there just isn’t that much surface area for issues to crop up.