tab-completion debug print

Hello.

I was reminded that I was often annoyed with identifying the code
that made a word-completion, by hearing the same complaint from a
collegue of mine just now.

Something like the attached that tweaks completion_matches calls
lets psql emit the line number where a word-completion
happens. The output can be split out using redirection so that it
doesn't break into the conversation on console.

(make -s COPT=-DTABCOMPLETION_DEBUG install)

$ psql postgres 2>~debug.out
=# alt[tab]er [tab]t[tab]ab[tab] [tab]

You can see the following output in another bash session.

$ tail -f ~/debug.out
[1414][1435][1435][1435][1431]

Every number enclosed by brackets is the line number in
tab-complete.c, where completion happens.

Is this useful? Any suggestions, thoughts?

regards.

--
Kyotaro Horiguchi
NTT Open Source Software Center