模式匹配erlang中的地图字段

Question

我目前正在读书＆lt;＆lt;编程Erlang，第2版＆gt;。当我查看Map＆＃39; s字段的模式匹配时，书中的代码片段在我的Erlang提示中抱怨一些错误。

%% Book's version
1> Henry8 = #{ class => king, born => 1491, died => 1547 }. 
#{ born => 1491, class=> king, died => 1547 }.
2> #{ born => B } = Henry8.
#{ born => 1491, class=> king, died => 1547 }.
3> B.
1491

%% My Eshell V6.2
65> Henry8 = #{ class => king, born => 1491, died => 1547 }.
#{born => 1491,class => king,died => 1547}
66> #{ born => B } = Henry8.
* 1: illegal pattern

我有什么遗失的吗？提前谢谢。

Answer 1

使用：=而不是=＆gt;

#{ born := B } = Henry8.

来源：http://erlang.org/doc/reference_manual/expressions.html#id79796