(|=>) : 'a -> 'b -> ('a, 'b) func

Gives a one-point finite partial function.

This is one of a suite of operations on finite partial functions, type ('a,'b)func. These may sometimes be preferable to ordinary functions since they permit more operations such as equality comparison, extraction of domain etc. The call x |=> y gives a finite partial function that maps x to y and is undefined for all arguments other than x.

  # let f = (1 |=> 2);;
  val f : (int, int) func = 

  # apply f 1;;
  val it : int = 2

  # apply f 2;;
  Exception: Failure "apply".

|->, apply, applyd, choose, combine, defined, dom, foldl, foldr, graph, is_undefined, mapf, ran, tryapplyd, undefine, undefined.