Erlang - record

定义一个record文件 1.erl:

-record(todo, {status=reminder, who=joe, text}).

定义并操纵记录：

1> rr("1.erl").

[todo]

2> X=#todo{}.

#todo{status = reminder,who = joe,text = undefined}

3> X1=#todo{status=urgent, text="Fix errata in book"}.

#todo{status = urgent,who = joe,text = "Fix errata in book"}

4> X2 = X1#todo{status=done}. %创建一个X1的副本，并将status字段设为done

#todo{status = done,who = joe,text = "Fix errata in book"}

从记录中提取字符串：

5> #todo{who=W, text=Txt} = X2.

#todo{status = done,who = joe,text = "Fix errata in book"}

6> W.

joe

7> Txt.

"Fix errata in book"

如果想提取某个字段的值，也可以

9> X2#todo.text.

"Fix errata in book"