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|
% generated: 8 March 1990
% option(s):
%
% meta_qsort
%
% Ralph M. Haygood
%
% meta-interpret Warren benchmark qsort
%
% For any meta-variable ~X~, interpret(~X~) behaves as if
%
% interpret(~X~):- ~X~.
%
% Thus, for example, interpret((foo(X), bar(X), !)) behaves as if
%
% interpret((foo(X), bar(X), !)):- foo(X), bar(X), !.
%
% Note that though ~X~ may contain cuts, those cuts cannot escape from
% interpret(~X~) to effect the parent goal; interpret(!) is equivalent
% to true.
%
% Cuts inside ~X~ are executed according to the rule that conjunction,
% disjunction, and if-then-else are transparent to cuts, and any other
% form is transparent to cuts if and only if it can be macro-expanded
% into a form involving only these three without interpret/1. If-then
% and negation are the only such other forms currently recognized; ( A
% -> B) is equivalent to ( A -> B ; fail ), and \+ A is equivalent to
% ( A -> fail ; true ).
meta_qsort(ShowResult) :-
interpret(qsort(R)),
( ShowResult = true ->
write(R), nl
; true).
interpret(Goal):-
interpret(Goal, Rest),
(nonvar(Rest), !, interpret(Rest)
;
true).
interpret(G, _):-
var(G),
!,
fail.
interpret((A, B), Rest):-
!,
interpret(A, Rest0),
(nonvar(Rest0) -> Rest = (Rest0, B)
; interpret(B, Rest)).
interpret((A ; B), Rest):-
!,
interpret_disjunction(A, B, Rest).
interpret((A -> B), Rest):-
!,
interpret_disjunction((A -> B), fail, Rest).
interpret(\+A, Rest):-
!,
interpret_disjunction((A -> fail), true, Rest).
interpret(!, true):-
!.
interpret(G, _):-
integer(G),
!,
fail.
interpret(G, _):-
is_built_in(G),
!,
interpret_built_in(G).
interpret(G, _):-
define(G, Body),
interpret(Body).
interpret_disjunction((A -> B), _, Rest):-
interpret(A, Rest0),
!,
(nonvar(Rest0) -> Rest = (Rest0 -> B)
; interpret(B, Rest)).
interpret_disjunction((_ -> _), C, Rest):- !,
interpret(C, Rest).
interpret_disjunction(A, _, Rest):-
interpret(A, Rest).
interpret_disjunction(_, B, Rest):-
interpret(B, Rest).
is_built_in(true).
is_built_in(_=<_).
is_built_in(write(_)).
interpret_built_in(true).
interpret_built_in(X=<Y):- X =< Y.
interpret_built_in(write(X)):- write(X), nl.
define(qsort(R),(
qsort([27,74,17,33,94,18,46,83,65, 2,
32,53,28,85,99,47,28,82, 6,11,
55,29,39,81,90,37,10, 0,66,51,
7,21,85,27,31,63,75, 4,95,99,
11,28,61,74,18,92,40,53,59, 8],R,[]))).
define(qsort([X|L],R,R0),(
partition(L,X,L1,L2),
qsort(L2,R1,R0),
qsort(L1,R,[X|R1]))).
define(qsort([],R,R),true).
define(partition([X|L],Y,[X|L1],L2),(
X=<Y,!,
partition(L,Y,L1,L2))).
define(partition([X|L],Y,L1,[X|L2]),(
partition(L,Y,L1,L2))).
define(partition([],_,[],[]),true).
% benchmark interface
benchmark(ShowResult) :-
meta_qsort(ShowResult).
:- include(common).
|
