谓词命令序列上的Prolog“运算符预期错误”

Question

我的学习材料中这个非常简单的Prolog示例给出了“操作员预期”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

与评论中提到的@larsman一样，将’和‘替换为'：

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