Provide a last function for lists

[heueristik]

There is a head function

head {A} (defaultValue : A) (list : List A) : A :=
  case list of
    | x :: _ := x
    | nil := defaultValue;

but no

last {A} (defaultValue : A) (list : List A) : A :=
  head@{
    defaultValue;
    list := reverse list;
  };

[mariari]

#139 fixes this issue

[lukaszcz]

I don't think we should have last. There are few legitimate use-cases for it. It's most often used incorrectly by beginners when they try to use lists as if they were arrays.

[lukaszcz]

We decided not to provide it, not in the Prelude at least.

[mariari]

Last comes up quite a bit with foldr patterns, it might be good to reconsider having it, as I'm not sure how else you'd give the first element to a foldr

[lukaszcz]

Whever you want to take the last element and then do foldr, you can reverse the list, take the first element and do foldl. But it's true taking the last element might be more intuitive, so we might want to reconsider this decision.