{-|
Module      : $HEADER$
Description : Extra functions on Maybe's.
Copyright   : (c) Justus Adam, 2015
License     : BDS3
Maintainer  : dev@justus.science
Stability   : experimental
Portability : POSIX, Windows
-}
{-# LANGUAGE UnicodeSyntax #-}
module Data.Maybe.JAExtra
  ( onlyIf
  ) where


{-|
  Contruct a value based on a boolean guard.

  >>> "blue" `onlyIf` (len [1] == 1)
  Just "blue"
-}
onlyIf ∷ α → Bool → Maybe α
onlyIf a True = Just a
onlyIf _ False = Nothing