[erlang-questions] Bound(?) var in anonymous fun

Loïc Hoguin <>
Tue Dec 18 12:36:25 CET 2012


This one only removes the first element. :)

On 12/18/2012 12:34 PM, Max Bourinov wrote:
> Or even more shooter:
>
> lists:delete(Key, StatusList).
>
>
> On Tue, Dec 18, 2012 at 3:22 PM, Dmitry Klionsky <
> <mailto:>> wrote:
>
>     On 12/18/2012 02:08 PM, Manuel A. Rubio "Bombadil" wrote:
>
>         Hi Pablo,
>
>         El 2012-12-18 11:54, Pablo Vieytes escribió:
>
>             I guessed Key was bound so I could use for pattern matching.
>             It's
>             very easy to fix it but I don't know why it doesn't work.
>
>
>         This doesn't works well because the params are not inside of
>         binding in closures. The params are the interface with the
>         outside world and will be confuse know if a param is a binding
>         or not. By default Erlang hasn't binding in function params.
>
>             Fixed version:
>
>             delete_key_from_list(Key, StatusList)->
>                  lists:foldr(
>                    fun(K, Acc) when K == Key ->
>                    Acc;
>               (Another, Acc) ->
>                    [Another|Acc]
>                    end,
>                    [],
>                    StatusList).
>
>
>         This code could be writted as:
>
>         delete_key_from_list(Key, StatusList)->
>              lists:filter(fun(X) -> Key =/= X end, StatusList).
>
>         Regards,
>         Manuel Rubio.
>         _________________________________________________
>         erlang-questions mailing list
>          <mailto:>
>         http://erlang.org/mailman/__listinfo/erlang-questions
>         <http://erlang.org/mailman/listinfo/erlang-questions>
>
>
>     Or even more readable as:
>
>     delete_key_from_list(Key, StatusList)->
>          [Status || Status <- StatusList, Status =/= Key].
>
>     --
>     Best regards,
>     Dmitry Klionsky
>
>
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>
>
>
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-- 
Loïc Hoguin
Erlang Cowboy
Nine Nines
http://ninenines.eu



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