{-# LANGUAGE NoImplicitPrelude #-}
{-# LANGUAGE Safe              #-}

module Bool
       ( whenM
       , unlessM
       , ifM
       , guardM
       , bool
       ) where

import           Control.Monad (Monad, MonadPlus, guard, unless, when, (=<<), (>>=))
import           Data.Bool     (Bool)
import           Data.Function (flip)

bool :: a -> a -> Bool -> a
bool f t p = if p then t else f

whenM :: Monad m => m Bool -> m () -> m ()
whenM p m =
  p >>= flip when m

unlessM :: Monad m => m Bool -> m () -> m ()
unlessM p m =
  p >>= flip unless m

ifM :: Monad m => m Bool -> m a -> m a -> m a
ifM p x y = p >>= \b -> if b then x else y

guardM :: MonadPlus m => m Bool -> m ()
guardM f = guard =<< f