具有确定性的成员/2的代码 [英] Code for member/2 with some Determinism

问题描述

我该如何编码对于最后一个具有确定性的member/2 元素.目前我正在使用:

How can I code member/2 that has determinism for the last element. Currently I am using:

member(X,[X|_]).
member(X,[_|Y]) :- member(X,Y).

当我查询以下内容时:

?- member(X,[1,2]).
X = 1 ;
X = 2 ;
No

解释器返回2后继续搜索，因为 还有一个选择点.我该如何实施member/2 这样就不会再发生了?

The interpreter continues searching after returning 2 since there is still a choice point left. How could I implement member/2 so that this does not happen anymore?

但是应该保留member/2的完整语义，即 答案如下:

But the full semantic of member/2 should be preserved, i.e. answers such as:

 ?- member(X,Y)
 Y = [X|_1] ;
 Y = [_1,X|_2] ;
 etc..

仍应按以前的方式工作.

Should still work as befor.

再见

推荐答案

member(B, [C|A]) :-
    member_(A, B, C).
member_(_, A, A).
member_([C|A], B, _) :-
    member_(A, B, C).

是在swi上进行两次列表调用的结果.

Is the result of two listing calls on swi.

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