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{-# LANGUAGE Trustworthy #-} {-# LANGUAGE NoImplicitPrelude #-}

-- | -- Module : Data.Bool -- Copyright : (c) The University of Glasgow 2001 -- License : BSD-style (see the file libraries/base/LICENSE)

-- Maintainer : libraries@haskell.org -- Stability : experimental -- Portability : portable

-- The 'Bool' type and related functions.

module Data.Bool ( -- * Booleans Bool(..), -- ** Operations (&&), (||), not, otherwise, bool, ) where

import GHC.Base

-- | Case analysis for the 'Bool' type. @'bool' x y p@ evaluates to @x@ -- when @p@ is 'False', and evaluates to @y@ when @p@ is 'True'.

-- This is equivalent to @if p then y else x@; that is, one can -- think of it as an if-then-else construct with its arguments -- reordered.

-- @since 4.7.0.0

-- ==== Examples

-- Basic usage:

-- >>> bool "foo" "bar" True -- "bar" -- >>> bool "foo" "bar" False -- "foo"

-- Confirm that @'bool' x y p@ and @if p then y else x@ are -- equivalent:

-- >>> let p = True; x = "bar"; y = "foo" -- >>> bool x y p == if p then y else x -- True -- >>> let p = False -- >>> bool x y p == if p then y else x -- True

bool :: a -> a -> Bool -> a bool f _ False = f bool _ t True = t