Question

我试图了解有关Prolog DCG规则的特殊情况会发生什么。规则是：

fizz_buzz(Msg) --> anything, fizz(Msg), anything, buzz, anything.

anything --> [].
anything --> [_], anything.

fizz(Msg) -->
    "fizz",
    {
        format('At fizz we have Msg=~w~n', [Msg])
    }.

buzz -->
    "buzz".

run :-
    atom_codes("blah blah fizz blah buzz", Codes),
    phrase(fiz_buzz(Msg), Codes),
    write(Msg).

得到了：

ERROR: phrase/3: Undefined procedure: fiz_buzz/3
ERROR:   However, there are definitions for:
ERROR:         fizz_buzz/3

我无法找到正确的短语＆＃34;运行这个语法。我犯了什么错误？

Answer 1

你有一个简单的拼写错误：尝试phrase(fizz_buzz(Msg),Codes),，你就会得到

?- run.
At fizz we have Msg=_G1212
_G1212
true

Prolog DCG短语错误

1 个答案: