[erlang-questions] Maps

[Loïc Hoguin]

On 05/14/2013 11:04 PM, Björn-Egil Dahlberg wrote:
>     It works fine if done in two steps (with the first step most likely
>     done in the function clause itself).
>
>     doit(M=#{ a := A=#{ b := B }}) ->
>        M#{ a := A#{ b := B + 4 }}.
>
>     Writing this I realize it's quite possible that you can already do
>     it with the current EEP. Am I right?
>
>
> Yes.
>
>
>     And it also fits:
>
>     doit(M=#{ a := A=#{ b := B }, aa := yes_do_it}) ->
>        M#{ a := A#{ b := B + 4 }, aa := done}.
>
>     You can already do this with records. Can we do this with maps too?
>     This + any type as key + dynamic is all I need.
>
>
> Yes. I had similar examples in the EEP but didn't nest the Maps.

Could be worth adding to the EEP so as to not forget to test it. Should 
I send a PR to your repository?

>     It would be cool if that could also be optimized at compile time,
>     though that's more of an edge case so understandable if that comes
>     later.
>
>
> What was it you said to me? "Make it work, make it pretty, make it
> fast." =) Still on step oneish.

Yep. It was just a suggestion that heavily hinted at "optimize for that 
case after everything else is optimized".

-- 
Loïc Hoguin
Erlang Cowboy
Nine Nines
http://ninenines.eu