Path: utzoo!attcan!uunet!lll-winken!lll-tis!helios.ee.lbl.gov!nosc!ucsd!rutgers!njin!princeton!mind!romero
From: romero@mind.UUCP (Antonio Romero)
Newsgroups: comp.lang.lisp
Subject: Disabling colons in CommonLisp
Keywords: help!
Message-ID: <2694@mind.UUCP>
Date: 1 Aug 88 15:35:21 GMT
Organization: Cognitive Science, Princeton University
Lines: 20


I'm currently porting a production system from FranzLisp to Lucid CommonLisp
2.1.1 running on a Sun.  I've run into a problem which I can't find a good
answer for, myself.  What i need to be able to do is end certain keywords in
the productions with colons -- e.g. "action:" or "belief:".  

My first thought was to try just making ":" into a macro character whose
associated function would return no values, so that colons effectively
disappear from the input stream.  This worked for most purposes, but broke
things like "(member 'someatom somelist :test 'equal)" because ":test" was
no longer recognized as a keyword-- all lisp ever saw was "(member 'someatom
somelist test 'equal)."  
My solution also made it impossible to reference symbols in other packages.

So I need a solution which would allow tokens to end in colons, without
breaking the other special interpretations associated with colons.
Ideally this would be possible within the CommonLisp standard, so as to be
portable, but I'll settle for a non-portable solution if I have to.
Has anyone out there solved this one already?

-Antonio Romero    romero@confidence.princeton.edu