-- |
-- Module      : OAlg.Data.Symbol
-- Description : character symbols
-- Copyright   : (c) Erich Gut
-- License     : BSD3
-- Maintainer  : zerich.gut@gmail.com
--
-- symbols from 'A' to 'Z'. They are mainly used to validate the
-- algebraic structure of 'OAlg.Structure.Multiplicative.Orientation'.
module OAlg.Data.Symbol
  ( Symbol(..), xSymbol
  )
  where

import Control.DeepSeq(NFData(..))

import OAlg.Data.X
import OAlg.Data.Validable

--------------------------------------------------------------------------------
-- Symbol -

-- | symbols from 'A' to 'Z'.
data Symbol
  = A | B | C | D | E | F | G | H | I | J | K | L | M
  | N | O | P | Q | R | S | T | U | V | W | X | Y | Z
  deriving (Show,Read,Eq,Ord,Enum,Bounded)

instance NFData Symbol where
  rnf A = ()
  rnf _ = ()

instance Validable Symbol where
  valid = rnfValid

instance XStandard Symbol where
  xStandard = xSymbol
  
--------------------------------------------------------------------------------
-- xSymbol -

-- | uniformly distributed random variable of 'Symbol'.
xSymbol :: X Symbol
xSymbol = xEnum