package alg_structs

Make (S) is a semigroup where op a b is...

• None if both a and b are None
• Some v if only one of a or b are Some v
• Some (S.op a' b') if b is Some b' and a is Some a'

This enables chains of associations over optional values that preserves any values that may be present. E.g.,

# module O = Semigroup.Option.Make ((val Semigroup.make ( * )));;
module O :
sig
  type t = int option
  val op : t -> t -> t
  val ( * ) : t -> t -> t
  val concat : t NonEmptyList.t -> t
end

# O.(Some 2 * None * None * Some 2);;
- : O.t = Option.Some 4

• parameter S

  An implementation of Semigroup

Parameters

Signature