insert' : ('a -> 'a -> bool) -> 'a -> 'a list -> 'a list

SYNOPSIS

Insert element into list unless it contains an equivalent one already.

DESCRIPTION

If r is a binary relation, x an element and l a list, the call insert' r x l will add x to the head of the list, unless the list already contains an element x' with r x x'; if it does, the list is returned unchanged. The function insert is the special case where r is equality.

FAILURE CONDITIONS

Fails only if the relation fails.

EXAMPLE

  # insert' (fun x y -> abs(x) = abs(y)) (-1) [1;2;3];;
  val it : int list = [1; 2; 3]

  # insert' (fun x y -> abs(x) = abs(y)) (-1) [2;3;4];;
  val it : int list = [-1; 2; 3; 4]