scsh bug ?

[Brian D. Carlstrom <bdc@martigny.ai.mit.edu>]

I'm reposting this for Bruno because he had trouble getting it through
to comp.lang.scheme.scsh and I don't have an answer.

-bri

------- start of forwarded message (RFC 934 encapsulation) -------
From: Bruno Verlyck <Bruno.Verlyck@inria.fr>
Subject: No sub-match found.
Newsgroups: comp.lang.scheme.scsh
Date: 25 Nov 1996 19:23:43 +0100

With scsh-0.4.4, if I do:

   (define m (string-match "(ab)?c" "c"))
   > (match:start m 1)

I get:

   Error: #{Procedure 7851 match:start}
          "No sub-match found."
          #{regexp-match}
          1
   1>

I see no accessible way (no module exporting a function) to know if sub-match 1
has matched nothing.  Is there another approved way I can't see, or is it time
to extend scsh-regexp-interface ?
------- end -------