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From: eijkhout@s41.csrd.uiuc.edu (Victor Eijkhout)
Newsgroups: comp.text.tex
Subject: Re: Want to extract words from a string
Message-ID: <1991Jan30.235332.18606@csrd.uiuc.edu>
Date: 30 Jan 91 23:53:32 GMT
References: <1991Jan30.213501.10838@midway.uchicago.edu>
Sender: news@csrd.uiuc.edu (news)
Organization: UIUC Center for Supercomputing Research and Development
Lines: 30

jeff@zem.uchicago.edu (Jeff Adler) writes:

>Suppose I have a string consisting of words separated by blanks.
>I would like a macro which returns the last word of the string,

>Example:
>	\lastword{one two three four}  yields		four

\def\lastword#1{\def\compare{zzz}%
    \xlastword#1 zzz }
%               ^   ^ two spaces

\def\xlastword#1 #2 {%
%               ^  ^ corresponding to these
    \def\test{#2}%
    \ifx\test\compare #1%
    \else \expandafter\xlastword \fi #2 }
%                                      ^ significant space
    
>and another macro which returns everything else.

replace \ifx line by

    \ifx\test\compare \accu
    \else \edef\accu{\accu #1 }%
          \expandafter\xlastwork \fi #2 }

and add \def\accu{ } somewhere in the beginning.

Victor.