Path: utzoo!utgpu!news-server.csri.toronto.edu!rutgers!usc!zaphod.mps.ohio-state.edu!van-bc!ubc-cs!alberta!ncc!isagate!steve
From: steve@edm.isac.CA (Steve Hole)
Newsgroups: comp.emacs
Subject: Re: Why does completion require an alist?
Keywords: completions alist
Message-ID: <1990Sep3.210627.19773@edm.isac.CA>
Date: 3 Sep 90 21:06:27 GMT
References: <9008311659.AA14901@STEVE-DALLAS.MIT.EDU> <Sep.1.03.08.23.1990.10801@sparky.rutgers.edu> <GF`%X?#@rpi.edu>
Reply-To: steve@edm.isac.ca (Steve Hole)
Organization: ISA Corporation
Lines: 25

This is something that I asked some time ago and got no response on.  I
thought then that I might have been set up that way in anticipation of
using it to something more interesting.   I modified the original
function (just prototyped as a lisp function for now), that uses the
second element in each dotted pair as a documentation string.  I had to
modify the display algorithm for the possible completions to display the
second element in a nice way in the possible completions list, but
voila, instant non-obtrusive selection menu.  I often do this kind of
thing: 

 (let ((my-list '(("joe" "This is option joe")
		  ("fred" "This is option fred")
		  ("henry" "This is option henry")
		  ("sam" "This is option sam"))))
   (setq response (completing-read "Which guy?" my-list nil t)))
		  

This lets me select from a set of options with encoded or non-obvious
values by attaching supplementary information to them.  Makes for
interfaces for my programming tools and all I have to do is define new
sets of lists for the things I would like them to select.
-- 
Steve Hole  		         mail: steve@edm.isac.ca
ISA Corp.			 uucp: !{uunet, alberta}!ncc!isagate!steve
Edmonton, Alberta, Canada       phone: (403) 441-4121