es signal catching

[Donn Cave <donn@u.washington.edu>]

I'm pretty sure there must be a simple answer to this.  I'm just trying
to set up a signal handler, to be in effect during the main loop of an
interactive session.  For example,  in  rc :

	; fn sigusr1 { echo caught SIGUSR1 }
	; kill -USR1 $pid
	caught SIGUSR1
	;

>From what I can see, es' signal trapping runs through the exception
mechanism, generating exceptions like ('signal' 'sigusr1').  That makes
it fairly simple to trap signals within a block of statements, but I'm
having trouble seeing how to achieve the effect illustrated above.

It seems to me that I want to be able to "catch" these exceptions in the
doit() loop, but I can't see how to do that.  (Haven't RTFM manual yet,
am waiting for someone to WTFM.)

	Donn Cave, University Computing Services, University of Washington
	donn@cac.washington.edu