以下是基于术语 equal/inequality的具体化。
首先,我们首先定义list_memberd_t/3
,它的行为就像 ,memberd_truth/3
但有不同的参数顺序:
list_memberd_t([] ,_,false).
list_memberd_t([Y|Ys],X,Truth) :-
if_(X=Y, Truth=true, list_memberd_t(Ys,X,Truth)).
list_memberd_truth(Xs,X,Truth) :- list_memberd_t(Xs,X,Truth).
为简洁起见,让我们定义memberd_t/3
基于list_memberd_t/3
:
memberd_t(X,Xs,Truth) :- list_memberd_t(Xs,X,Truth).
作为平行于library(apply)
,让我们定义tinclude/3
:
:- meta_predicate tinclude(2,?,?).
tinclude(P_2,Xs,Zs) :-
list_tinclude_list(Xs,P_2,Zs).
list_tinclude_list([], _P_2,[]).
list_tinclude_list([E|Es],P_2,Fs0) :-
if_(call(P_2,E), Fs0 = [E|Fs], Fs0 = Fs),
list_tinclude_list(Es,P_2,Fs).
tfilter/3
是 的另一个名称tinclude/3
:
tfilter(P_2,As,Bs) :-
tinclude(P_2,As,Bs).
接下来,我们定义元谓词texclude/3
,它的反面tinclude/3
:
:- meta_predicate texclude(2,?,?).
texclude(P_2,Xs,Zs) :-
list_texclude_list(Xs,P_2,Zs).
list_texclude_list([],_,[]).
list_texclude_list([E|Es],P_2,Fs0) :-
if_(call(P_2,E), Fs0 = Fs, Fs0 = [E|Fs]),
list_texclude_list(Es,P_2,Fs).
现在让我们一起使用它们!
?- texclude(list_memberd_truth([a,e,i,o,u]),
[d,e,l,e,t,e,' ',v,o,w,e,l,s,' ',i,n,' ',a,' ',l,i,s,t], Filtered).
Filtered = [d, l, t, ' ',v, w, l,s,' ', n,' ', ' ',l, s,t].
编辑
作为使用 above 的替代方法texclude/3
,让我们使用tinclude/3
辅助谓词not/3
来翻转真值:
:- meta_predicate not(2,?,?).
not(P_2,X,Truth) :-
call(P_2,X,Truth0),
truth_flipped(Truth0,Truth).
truth_flipped(true,false).
truth_flipped(false,true).
示例查询:
?- tinclude(not(list_memberd_truth([a,e,i,o,u])),
[d,e,l,e,t,e,' ',v,o,w,e,l,s,' ',i,n,' ',a,' ',l,i,s,t], Filtered).
Filtered = [d, l, t, ' ',v, w, l,s,' ', n,' ', ' ',l, s,t].