Erlang/OTP 17.0 has been released
Erlang/OTP 17.0发布了,不过Maps相关的设计还没有尘埃落定,目前:
With Maps you may for instance:
-- M0 = #{ a => 1, b => 2}, % create associations
-- M1 = M0#{ a := 10 }, % update values
-- M2 = M1#{ "hi" => "hello"}, % add new associations
-- #{ "hi" := V1, a := V2, b := V3} = M2. % match keys with
values
For information on how to use Maps please see the Reference
Manual.
The current implementation is without the following features:
-- No variable keys
-- No single value access
-- No map comprehensions
Note that Maps is experimental during OTP 17.0.
另外有一个不兼容的情况: OTP-11782 == erts ==
The external format for Maps has changed in a way that is not compatible with the format used in OTP 17.0-rc1 and OTP 17.0-rc2.
在这里查看详情:
Change the subtag used for maps from 0xB to 0xF
Maps 模块对应的文档位置
http://erlang.org/doc/man/maps.html
占坑,后续变动将在此更新.
Learn You Some Erlang 对Maps内容的增补章节
顺便补几张图:
上面的图看不懂?可以参考下面这篇论文,其中简要介绍了Erlang的Tag-Scheme,或者可以去看下本文的第一篇 http://www.cnblogs.com/me-sa/p/when_we_talk_about_erlang_maps_1.html
On Preserving Term Sharing in the Erlang Virtual Machine
摘要:In this paper we describe our experiences and argue through examples why flattening terms during copying is not a good idea for
a language like Erlang. More importantly, we propose a sharing preserving copying mechanism for Erlang/OTP and describe a pub-
licly available complete implementation of this mechanism.
