Path: utzoo!attcan!uunet!cs.utexas.edu!hellgate.utah.edu!cdr.utah.edu!moore
From: moore%cdr.utah.edu@cs.utah.edu (Tim Moore)
Newsgroups: comp.lang.lisp
Subject: Re: Case sensitivity (Ugh, Again!)
Message-ID: <1991Jan9.095506.29341@hellgate.utah.edu>
Date: 9 Jan 91 16:55:06 GMT
References: <2872363025@ARTEMIS.cam.nist.gov>
Organization: University of Utah CS Dept
Lines: 37

In article <2872363025@ARTEMIS.cam.nist.gov> miller@GEMcam.nist.gov (Bruce R. Miller) writes:
>
>I'm given to understand that Allegro common lisp has a form
>
>    (set-case-mode :case-sensitive-lower)  
>
>such that, afterwards, Lisp code is case sensitive and to access the
>`standard' lisp, one must type in lowercase.
>Presumably there are :case-sensitive-upper, etc. variants.
>Note, I'm not just talking about a case-sensitive readtable.
>
>This has me wondering...

>  2) Is there anything like this slated to be part of CL?  Do other
>implementations provide a similar hack?

In the proposed ANSI standard (and CLtL2) readtables have a
READTABLE-CASE slot that can be one of :UPCASE, :DOWNCASE, :PRESERVE,
or :INVERT. To quote CLtL2,

"For :upcase, replaceable characters are converted to uppercase. (This
was the behavior specified by the first edition.)

For :downcase, replaceable characters are converted to lowercase.

For :preserve, the cases of all characters remain unchanged.

For :invert, if all of the replaceable letters in the extended token
are of the same case, they are all converted to the opposite case;
otherwise the cases of all characters in that token remain unchanged."

Utah Common Lisp implements this; presumably others do or are about
to.

Tim Moore                    moore@cs.utah.edu {bellcore,hplabs}!utah-cs!moore
"Ah, youth. Ah, statute of limitations."
		-John Waters