Vertical.hs

{-
	Copyright (C) 2021 Dr. Alistair Ward

	This file is part of BishBosh.

	BishBosh is free software: you can redistribute it and/or modify
	it under the terms of the GNU General Public License as published by
	the Free Software Foundation, either version 3 of the License, or
	(at your option) any later version.

	BishBosh is distributed in the hope that it will be useful,
	but WITHOUT ANY WARRANTY; without even the implied warranty of
	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
	GNU General Public License for more details.

	You should have received a copy of the GNU General Public License
	along with BishBosh.  If not, see <http://www.gnu.org/licenses/>.
-}
{- |
 [@AUTHOR@]	Dr. Alistair Ward

 [@DESCRIPTION@]

	* Describes the direction of a file of the board.
-}

module BishBosh.Direction.Vertical(
-- * Types
-- ** Data-types
	Vertical(),
-- * Constants
--	verticals,
	nVerticals
) where

import qualified	BishBosh.Property.FixedMembership	as Property.FixedMembership
import qualified	BishBosh.Property.Opposable		as Property.Opposable
import qualified	BishBosh.Property.Reflectable		as Property.Reflectable
import qualified	BishBosh.Type.Count			as Type.Count

-- | The sum-type of orientations of all lines of constant file.
data Vertical	= S | N deriving (Enum, Eq, Ord, Show)

instance Read Vertical where
	readsPrec _ ('S' : s)	= [(S, s)]
	readsPrec _ ('N' : s)	= [(N, s)]
	readsPrec _ _		= []	-- No parse.

instance Property.FixedMembership.FixedMembership Vertical where
	members	= verticals

instance Property.Opposable.Opposable Vertical where
	getOpposite S	= N
	getOpposite N	= S

instance Property.Reflectable.ReflectableOnX Vertical where
	reflectOnX	= Property.Opposable.getOpposite

-- | Constant range of values.
verticals :: [Vertical]
verticals	= [ toEnum 0 .. ]

-- | The number of verticals directions.
nVerticals :: Type.Count.NDirections
nVerticals	= fromIntegral $ length verticals