Path: utzoo!utgpu!news-server.csri.toronto.edu!mailrus!ncar!noao!arizona!debray
From: debray@cs.arizona.edu (Saumya K. Debray)
Newsgroups: comp.lang.prolog
Subject: Re: Simple Prolog Question
Message-ID: <24120@megaron.cs.arizona.edu>
Date: 10 Aug 90 17:04:15 GMT
References: <2157@cernvax.UUCP> <3542@goanna.cs.rmit.oz.au>
Organization: U of Arizona CS Dept, Tucson
Lines: 30

Richard A. O'Keefe (ok@goanna.cs.rmit.oz.au) writes:

> A pure way of doing it is
> 
> 	remove_leading_blanks([],    []).
> 	remove_leading_blanks([H|T], [H|T]) :- H =\= " ".
> 	remove_leading_blanks([H|T], R    ) :- H =:= " ",
> 		remove_leading_blanks(T, R).
> 
> If you don't mind a red cut, you can do
> 
> 	remove_leading_blanks([32|T], R) :- !,
> 		remove_leading_blanks(T, R).
> 	remove_leading_blanks(T, R).

I think I would prefer the following ("look, Ma, no choice points"):

	remove_leading_blanks([], []).
	remove_leading_blanks([H|T], L) :-
	     H =:= " " ->
	          remove_leading_blanks(T, L) ;
		  L = [H|T].



-- 
Saumya Debray		CS Department, University of Arizona, Tucson

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