General.hs

{- |
Module      : Data.Set.Range.General
Description : General functions that provide information about a range set.
Copyright   : (c) 2017 Daniel Lovasko
License     : BSD2

Maintainer  : Daniel Lovasko <daniel.lovasko@gmail.com>
Stability   : stable
Portability : portable
-}

module Data.Set.Range.General
( empty
, null
, size
) where

import qualified Data.List as L
import Prelude hiding (null)

import Data.Set.Range.Types


-- | Create an empty range set.
empty
  :: RangeSet a -- ^ range set
empty = []

-- | Test if the range set does not contain any points.
null
  :: RangeSet a -- ^ range set
  -> Bool       -- ^ decision
null [] = True
null _  = False

-- | Count the number of unique points stored in the range set.
size :: (Num n, Enum a)
  => RangeSet a -- ^ range set
  -> n          -- ^ number of points
size xs = sum $ map (L.genericLength . uncurry enumFromTo) xs