Erlang: elegant tuple_to_list/1

erlang, functional-programming

Solution

I think your function is ok, and more if your goal is to learn the language. As a matter of style, usually the base case when constructing lists is just the empty list []. So I'd write

tup2list(Tuple) -> tup2list(Tuple, 1, tuple_size(Tuple)).

tup2list(Tuple, Pos, Size) when Pos =< Size ->  
    [element(Pos,Tuple) | tup2list(Tuple, Pos+1, Size)];
tup2list(_Tuple,_Pos,_Size) -> [].

you can write pretty much the same with list comprehension

[element(I,Tuple) || I <- lists:seq(1,tuple_size(Tuple))].

it will work as expected when the tuple has no elements, as lists:seq(1,0) gives an empty list.

Problem

I'm getting myself introduced to Erlang by Armstrongs "Programming Erlang". One Exercise is to write a reeimplementation of the tuple_to_list/1 BIF. My solution seems rather inelegant to me, especially because of the helper function I use. Is there a more Erlang-ish way of doing this? ``` tup2lis({}) -> []; tup2lis(T) -> tup2list_help(T,1,tuple_size(T)). tup2list_help(T,Size,Size) -> [element(Size,T)]; tup2list_help(T,Pos,Size) -> [element(Pos,T)|tup2list_help(T,Pos+1,Size)]. ``` Thank you very much for your ideas. :)

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