谓词命令序列上的 Prolog "operator expected error"

Question

这个非常简单的Prolog示例来自我的学习材料，给了我一个"Operator Expected"错误:

greet(alice):- 
        write(‘How are you doin, pal?’).
greet(bob):- 
        write(‘Awfully nice to see you!’).

我错过了什么

Answer 1

就像评论中提到的@larsman一样，用'代替’和‘:

greet(alice):-
        write('How are you doin, pal?').
greet(bob):-
        write('Awfully nice to see you!').