\DOC front_last

\TYPE {Lib.front_last : 'a list -> 'a list * 'a}

\SYNOPSIS
Takes a non-empty list {L} and returns a pair {(front,last)} such that
{front @ [last] = L}.

\KEYWORDS
list.

\FAILURE
Fails if the list is empty.

\EXAMPLE
{
- front_last [1];
> val it = ([],1) : int list * int

- front_last [1,2,3];
> val it = ([1,2],3) : int list * int
}


\SEEALSO
Lib.butlast, Lib.last.
\ENDDOC