[erlang-questions] LFE - Lisp Flavoured Erlang released

[Kevin Scaldeferri]

On Mar 10, 2008, at 3:44 PM, Kevin Scaldeferri wrote:

>
> On Mar 10, 2008, at 2:11 PM, Torbjorn Tornkvist wrote:
>
>>
>> Perhaps a stupid question. Do LFE implement currying?
>> If not, why?
>>
>> I want currying... :-)
>>
>
> Here's something I threw together in a couple minutes:
>
> %% F({a,b}) -> F'(a,b)
> curry(F, Arity) ->
>     if
>         Arity =:= 1 -> fun(A)         -> F({A}) end;
>         Arity =:= 2 -> fun(A,B)       -> F({A,B}) end;
>         Arity =:= 3 -> fun(A,B,C)     -> F({A,B,C}) end;
>         Arity =:= 4 -> fun(A,B,C,D)   -> F({A,B,C,D}) end;
>         Arity =:= 5 -> fun(A,B,C,D,E) -> F({A,B,C,D,E}) end;
>         true -> throw(unsupported_arity)
>     end.
>

Should do slightly more browsing of the docs before posting :-).  This  
is a slight improvement:

%% F({a,b}) -> F'(a,b)
curry(F) ->
     {arity, Arity} = erlang:fun_info(F, arity),
     if
         Arity =:= 1 -> fun(A)         -> F({A}) end;
         Arity =:= 2 -> fun(A,B)       -> F({A,B}) end;
         Arity =:= 3 -> fun(A,B,C)     -> F({A,B,C}) end;
         Arity =:= 4 -> fun(A,B,C,D)   -> F({A,B,C,D}) end;
         Arity =:= 5 -> fun(A,B,C,D,E) -> F({A,B,C,D,E}) end;
         true -> throw(unsupported_arity)
     end.