Path: utzoo!utgpu!news-server.csri.toronto.edu!rpi!zaphod.mps.ohio-state.edu!usc!snorkelwacker.mit.edu!stanford.edu!neon.Stanford.EDU!michaelg
From: michaelg@neon.Stanford.EDU (Michael Greenwald)
Newsgroups: comp.lang.lisp
Subject: Re: zeta lisp
Message-ID: <1991Apr9.202309.23949@neon.Stanford.EDU>
Date: 9 Apr 91 20:23:09 GMT
References: <1991Apr09.110422.19604@kub.nl>
Organization: Computer Science Department, Stanford University, Ca , USA
Lines: 37

pberck@kub.nl (Peter Berck) writes:

>I know it's a long shot, but does anyone know what this does:

>(........
>            (AND (STRING-EQUAL (STRING-CADR L) "j")
>                 (zl:MEM #'STRING-EQUAL
>                         (STRING-CAR (STRING-LAST MEM)) '("e" "a" "o"))))))

>I am 'translating' a program written in ZetaLisp for someone, and I am
>not sure what (zl:MEM ... ..) does, because I don't have the zl
>package. He is away for a week, so I can't ask him, ... so I am trying
>it this way.

(ZL:MEM pred item list) is just like ZL:MEMQ, except that it uses the two
argument pred for comparison instead of EQ.  (Or you could say that it
is just like MEMBER, except it takes a predicate instead of EQL).  By
the way, MEMQ is from MACLISP, so it isn't such a "long shot".  

Anyway, MEM returns NIL if "item" isn't in "list" according to "pred".
If item >is< in the list, then MEM returns the first CONS with
something matching item as its CAR (or, as they say, "the SUBLIST
starting with ITEM")

If ZL:MEM shows up someplace else, and has a non-commutative pred (like
#'char-lessp), then you should know "item" is always the first
argument passed to pred.

>it looks like some sort of mapping function (?). MEM is (also) a
>variable defined in the DO loop where this happens...

>thanks for any help
>-peter


>--------------------------------------
>pberck@kub.nl     -     kubvx1::berckp