Erlang: is it possible to write the minimum function as a list fold?

Question

Given a function:

min(A, B)  when A =< B -> A;
min(_A, B)             -> B.

can I use this in the function foldlin a similar fashion to this:

lists:foldl(fun min/2, 0, [1,2,3,4,5,6,7,8,9,10])

I believe it is not possible, because I have to set an initial value that will be compared to the rest of the list, e. g. there is no identity function that I can think of. Am I right?

Syntax is written in Erlang, but should be readable for non Erlang programmers, too.

Answer 1

min(List) ->
    Min = fun(A,  B) when A < B -> A;
             (_A, B)            -> B end,
    lists:foldl(Min, undefined, List).

Using undefined as the initial state should do the trick. Returns undefined for an empty list, which is kind of nice as an API.

If you want it to crash on an empty list, use this function header instead:

min([Head|Rest]) ->
    Min = fun(A,  B) when A < B -> A;
             (_A, B)            -> B end,
    lists:foldl(Min, Head, Rest).