Path: utzoo!utgpu!news-server.csri.toronto.edu!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: hard to write (was Re: STRUCTUREP)
Message-ID: <1990Oct14.185715.11441@hellgate.utah.edu>
Date: 15 Oct 90 00:57:15 GMT
Lines: 26

-1~
In article <761@forsight.Jpl.Nasa.Gov> gat@robotics.Jpl.Nasa.Gov (Erann Gat) writes: 
>
>EQUAL doesn't descend structures!  That was news that sent me scurrying to
>CLTL2, and indeed it is so.  But then I found the following puzzling
>"Clarification": The predicate EQUALP, it says, never descends structures
>either.  (Actually what it says is that it never recursively descends
>any structure or data type other than conses, arrays and pathnames.)  It
>then goes on (on p. 109) to describe how EQUALP compares structures!  So
>can you compare structures or not?
>
>E.
Organization: University of Utah CS Dept
References: <1990Oct10.130925.18317@hellgate.utah.edu> <756@forsight.Jpl.Nasa.Gov> <3534@skye.ed.ac.uk> <761@forsight.Jpl.Nasa.Gov>

EQUALP should compare DEFSTRUCT structures as described on p. 109. The
translation from X3J13 cleanup issue to CLtL2 was somewhat garbled,
possibly because the cleanup issue was revised several times. Also,
there is some overloading of the term "structure"; in the early parts
of equalp's description it means "any structured datatype with
components", whereas on p.109 it means "DEFSTRUCT object". The cleanup
issue uses more consistent terminology.

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