Prolog类型不兼容(Prolog type is incompatible)

Prolog类型不兼容(Prolog type is incompatible)

Visual Prolog 8抛出错误c504：表达式具有类型'（） - > :: char procedure'，它与类型':: char'不兼容。

main.pro

implement main open core, console class predicates цикл : (). print : (). clauses цикл(). print() :- console::initUtf8(), цикл, C = readChar, /* Читать символ и связывать его с переменной C */ write(C), C1 = convert(char, C), C2 = convert(char, '\r'). C1 = C2. /* Является ли введенный символ возвратом каретки? fail, если нет */ run() :- цикл, fail. run() :- succeed. % place your own code here end implement main goal mainExe::run(main::run).

怎么解决呢？

Visual Prolog 8 throws error c504 : The expression has type '() -> ::char procedure', which is incompatible with the type '::char'.

main.pro

implement main open core, console class predicates цикл : (). print : (). clauses цикл(). print() :- console::initUtf8(), цикл, C = readChar, /* Читать символ и связывать его с переменной C */ write(C), C1 = convert(char, C), C2 = convert(char, '\r'). C1 = C2. /* Является ли введенный символ возвратом каретки? fail, если нет */ run() :- цикл, fail. run() :- succeed. % place your own code here end implement main goal mainExe::run(main::run).

How can to fix it?

最满意答案

你似乎有错误：

    print() :-
        ....
        цикл,
        C = readChar,       % <<-------
 
 你应该这样写 
 
        C = readChar(), 
 在手册中搜索readChar时，可以看到建议的用法 
 
 
 
 _ = console :: readChar（）。 
 
 
 似乎错误消息暗示相同： readChar “是类型() -> char 。” ，而不是“一个char ” 。 你的C是个char 。 要从过程中获取结果，我们通常需要运行它（此“运行”与在代码中run无关）。 
You seem to have the error here:
 
    print() :-
        ....
        цикл,
        C = readChar,       % <<-------
 
You should write it like this
 
        C = readChar(), 
as searching for readChar in the manual reveals, where one can see the suggested usage as 
 
 
 
_ = console::readChar().
 
 
Seem that the error message suggests the same: readChar "is a procedure of type () -> char.", not "a char". Your C is a char. To get the result from a procedure we usually need to run it (this "run" is unrelated to run in your code).