[erlang-questions] Maps single value access not implemented

Loïc Hoguin <>
Mon Feb 10 10:01:43 CET 2014


On 02/10/2014 03:39 AM, Sina Samavati wrote:
> Charles Irvine <> writes:
>
>> I am wanting to experiment with Maps in R17, but just discovered that
>> accessing a single value from a map is not yet implemented. I find
>> this surprising. Isn’t this a most fundamental feature of a map data
>> structure?
>
> Yes, this is.

No it's not.

Personally I find it completely unnecessary. Look at how records are 
used, people tend to match everything they need in the function head 
because it makes the code clearer. It'll be the same with maps. It'd
really only be useful in the shell because there's no function heads
there.

> Note that the latest version is *17.0-rc1* which means it is a _pre-release_.
> We will probably see the complete implementation of Maps[1] in 17.0-rc2.

No it will not be complete. Variables as key will most likely not be 
ready for R17. Large maps will also be slow. What you have now is pretty 
much what you will get, as the focus is on stabilizing what's done so 
far, rather than risk shipping breaking bugs.

-- 
Loïc Hoguin
http://ninenines.eu



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