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Re: cmdline.ss library in PLT

This page is part of the web mail archives of SRFI 37 from before July 7th, 2015. The new archives for SRFI 37 contain all messages, not just those from before July 7th, 2015.

On Wed, 25 Sep 2002, Robert Bruce Findler wrote:

> Beyond this problem, are there other problems? One question I have: how
> could one implement the once-any specifier in the cmdline.ss library?

Good question.

I would argue that "once-any" options are actually modes. I would use the
main set of "once-any" options as the first operand (instead of an
option), and make the minor "once-any" option sets arguments their common
"mode option".

Of course, sometimes we must match an existing interfaces. In this case, I
would use an option table (passed from option processor to option
processor). I would use a single "mode entry" in this table for each group
of "once-any" options. The option processor for each "once-any"  option
could check its "mode entry", and issue an error or warning if a mode was
already selected.

  -Anthony Carrico