Artifact d2e2ad57494d966de27797fd028c767c29f60924da546c22363683ac53c57f98:

• File psl-1983/3-1/kernel/sets.red — part of check-in [eb17ceb7f6] at 2020-04-21 19:40:01 on branch master — Add Reduce 3.0 to the historical section of the archive, and some more
  files relating to version sof PSL from the early 1980s. Thanks are due to
  Paul McJones and Nelson Beebe for these, as well as to all the original
  authors.

  git-svn-id: https://svn.code.sf.net/p/reduce-algebra/code/historical@5328 2bfe0521-f11c-4a00-b80e-6202646ff360 (user: arthurcnorman@users.sourceforge.net, size: 1622) [annotate] [blame] [check-ins using] [more...]

• File psl-1983/kernel/sets.red — part of check-in [eb17ceb7f6] at 2020-04-21 19:40:01 on branch master — Add Reduce 3.0 to the historical section of the archive, and some more
  files relating to version sof PSL from the early 1980s. Thanks are due to
  Paul McJones and Nelson Beebe for these, as well as to all the original
  authors.

  git-svn-id: https://svn.code.sf.net/p/reduce-algebra/code/historical@5328 2bfe0521-f11c-4a00-b80e-6202646ff360 (user: arthurcnorman@users.sourceforge.net, size: 1622) [annotate] [blame] [check-ins using]

%
% SETS.RED - Functions acting on lists as sets
% 
% Author:      Eric Benson
%	       Symbolic Computation Group
%              Computer Science Dept.
%              University of Utah
% Date:        12 December 1981
% Copyright (c) 1981 University of Utah
%

lisp procedure List2Set L;		%. Remove redundant elements from L
    if not PairP L then NIL
    else if car L member cdr L then List2Set cdr L
    else car L . List2Set cdr L;

lisp procedure List2SetQ L;		%. EQ version of List2Set
    if not PairP L then NIL		% Don't confuse it with SetQ!
    else if car L memq cdr L then List2Set cdr L
    else car L . List2Set cdr L;

lisp procedure Adjoin(Element, ASet);	%. Add Element to Set
    if Element member ASet then ASet else Element . ASet;

lisp procedure AdjoinQ(Element, ASet);	%. EQ version of Adjoin
    if Element memq ASet then ASet else Element . ASet;

lisp procedure Union(X, Y);		%. Set union
    if not PairP X then Y
    else Union(cdr X, if car X Member Y then Y else car X . Y);

lisp procedure UnionQ(X, Y);		%. EQ version of UNION
    if not PairP X then Y
    else UnionQ(cdr X, if car X memq Y then Y else car X . Y);

lisp procedure XN(U, V);		%. Set intersection
    if not PairP U then NIL
    else if car U Member V then car U . XN(cdr U, Delete(car U, V))
    else XN(cdr U, V);

lisp procedure XNQ(U, V);		%. EQ version of XN
    if null PairP U then NIL
    else if car U memq V then car U . XN(cdr U, DelQ(car U, V))
    else XN(cdr U, V);

LoadTime
<<  PutD('Intersection, 'EXPR, cdr GetD 'XN);	% for those who like to type
    PutD('IntersectionQ, 'EXPR, cdr GetD 'XNQ) >>;

END;