带变量的 Prolog DCG

Question

我有两个人的DCG句子，代表一男一女。我想用 "he" 或 "she" 来指代上一句中提到的人。

假设我们有这些 DCG：

father --> [Peter].
mother --> [Isabel].

child --> [Guido].
child --> [Claudia].

verb --> [is].
relation --> [father, of].
relation --> [mother, of].

pronoun --> [he].
pronoun --> [she].

adjective --> [a, male].
adjective --> [a, female].

s --> father, verb, relation, child.
s --> mother, verb, relation, child.
s --> pronoun, verb, adjective.

正在查询 ?- s([Peter, is, father, of, Guido], []). returns true.

我如何才能确保现在查询 ?- s([he, is, a, male], []). 时应该 return true 只是因为我在上一句中已经提到了 Peter（男性）。否则应该 return false.

此题使用与相同的例子。

Answer 1

您可以增强您的 DCG 以保持某种状态（最后一句话的性别）：

father --> ['Peter'].
mother --> ['Isabel'].

child --> ['Guido'].
child --> ['Claudia'].

verb --> [is].
relation --> [father, of].
relation --> [mother, of].

pronoun(he) --> [he].
pronoun(she) --> [she].

adjective --> [a, male].
adjective --> [a, female].

s(G) --> s(none,G).

s(_,he) --> father, verb, relation, child.
s(_,she) --> mother, verb, relation, child.
s(G,G) --> pronoun(G), verb, adjective.

现在您可以使用此状态链接查询：

?- phrase(s(G1),['Peter', is, father, of, 'Guido']), phrase(s(G1,G2),[he, is, a, male]).
G1 = G2, G2 = he

您可能需要稍微修改 DCG 以约束关系（使用性别参数）。例如，您的 DCG 目前接受 'Peter' is mother of 'Guido'，我不确定这是有意的。

带变量的 Prolog DCG

Prolog DCG with variables

prolog

dcg