I'm happy to report success on two fronts (using procmail 3.11pre7):
1. The method I suggested Thursday or Friday for using procmail to trigger
once-a-day maintenance tasks when the first incoming message of the day
arrives (on a system where you have no cron access, of course; otherwise
cron is preferable) worked very well on its first try. The slight draw-
back is the extra kilobyte in my disk usage for a twenty-byte file, but
one shell a day is preferable to ls or date (or certainly perl!) for every
incoming message.
2. Yes, procmail is smart enough to know when a series is converging and
not to keep looking for more occurrences of the expression when the
increments for each new appearance are below the resolution of the math
library. This:
* 1^.5 ^
scored 2 and did not hang.
Unfortunately, when it comes to recording scores of individual conditions
in a verbose logfile or to sourcing $=, procmail rounds to the nearest
integer, so it isn't always easy to tell.