% ==========================================================================
% $Id: list_delete.pl,v 1.1 2014/01/21 04:50:36 jlang Exp $
% CSI2120 example Code for lecture 5
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% (C)opyright:
%
%   Jochen Lang
%   EECS, University of Ottawa
%   800 King Edward Ave.
%   Ottawa, On., K1N 6N5
%   Canada. 
%   http://www.eecs.uottawa.ca/~jlang
% 
% Creator: jlang (Jochen Lang) based on Clocksin & Mellish
% Email:   jlang@eecs.uottawa.ca
% ==========================================================================
% $Log: list_delete.pl,v $
% Revision 1.1  2014/01/21 04:50:36  jlang
% Added further list processing for lecture 5.
%
% ==========================================================================
% Delete element from front
deleteFront(R,[R|L],L).	% Element found 
deleteFront(R,[X|LL],[X|L]) :-
	deleteFront(R,LL,L).	% Use Accumulator 

% Delete all occurrences of an element
deleteAll(_,[],[]).
deleteAll(X,[X|T],Result) :- 
	deleteAll(X,T,Result),!.	% Delete once
deleteAll(X,[H|T],[H|Result]) :-
	deleteAll(X,T,Result).	% Other element