Supersort.hs

-- | This module provides functions for creating Supersort variants for
--   adjudicating between 3 sorting algorithms.
module Data.Tensort.Subalgorithms.Supersort
  ( supersort,
    mundaneSuperStrat,
    magicSuperStrat,
  )
where

import Data.Tensort.Utils.Types (SortAlg, SupersortStrat)

-- | Used for creating a Supersort algorithm that adjudicates between 3 sorting
--   algorithms.
--
--   Takes 3 sorting algorithms and a SuperStrat and returns a SortAlg that
--   adjudicates between the 3 sorting algorithms using the provided
--   SuperStrat.

-- | ==== __Examples__
-- >>> import Data.Tensort.Subalgorithms.Bubblesort (bubblesort)
-- >>> import Data.Tensort.Subalgorithms.Permutationsort (permutationsort)
-- >>> import Data.Tensort.OtherSorts.Mergesort (mergesort)
--
-- >>> supersort (mergesort, bubblesort, permutationsort, mundaneSuperStrat) ([16, 23, 4, 8, 15, 42] :: [Int])
-- [4,8,15,16,23,42]
--
-- >>> supersort (mergesort, bubblesort, permutationsort, mundaneSuperStrat) ([(16, 23), (4, 8), (15, 42)] :: [(Int, Int)])
-- [(4,8),(15,42),(16,23)]
supersort ::
  (Ord a) =>
  (SortAlg a, SortAlg a, SortAlg a, SupersortStrat a) ->
  [a] ->
  [a]
supersort (subAlg1, subAlg2, subAlg3, superStrat) xs =
  if result1 == result2
    then result1
    else superStrat (result1, result2, subAlg3 xs)
  where
    result1 = subAlg1 xs
    result2 = subAlg2 xs

-- | Takes 3 SortAlgs and adjudicates between them to find a common result.
--   Optimized for use in Mundane Robustsort variants.

-- | ==== __Examples__
-- >>> import Data.Tensort.Subalgorithms.Bubblesort (bubblesort)
-- >>> import Data.Tensort.OtherSorts.Mergesort (mergesort)
-- >>> import Data.Tensort.Subalgorithms.Permutationsort (permutationsort)
--
-- >>> supersort (mergesort, bubblesort, permutationsort, mundaneSuperStrat) ([16, 23, 4, 8, 15, 42] :: [Int])
-- [4,8,15,16,23,42]
--
-- >>> supersort (mergesort, bubblesort, permutationsort, mundaneSuperStrat) ([(16, 23), (4, 8), (15, 42)] :: [(Int, Int)])
-- [(4,8),(15,42),(16,23)]
mundaneSuperStrat :: (Ord a) => SupersortStrat a
mundaneSuperStrat (result1, result2, result3) =
  if result2 == result3 then result2 else result1

-- | Takes 3 SortAlgs and adjudicates between them to find a common result.
--   Optimized for use in Magic Robustsort variants.
--
--   Previously we used different SuperStrats for Mundane and Magic Supersorts.
--   Currently there is no need to differentiate, but we keep this here for
--   backwards compatibility and in case this changes again in the future.

-- | ==== __Examples__
-- >>> import Data.Tensort.Subalgorithms.Bubblesort (bubblesort)
-- >>> import Data.Tensort.OtherSorts.Mergesort (mergesort)
-- >>> import Data.Tensort.Subalgorithms.Permutationsort (permutationsort)
--
-- >>> supersort (mergesort, bubblesort, permutationsort, magicSuperStrat) ([16, 23, 4, 8, 15, 42] :: [Int])
-- [4,8,15,16,23,42]
--
-- >>> supersort (mergesort, bubblesort, permutationsort, magicSuperStrat) ([(16, 23), (4, 8), (15, 42)] :: [(Int, Int)])
-- [(4,8),(15,42),(16,23)]
magicSuperStrat :: (Ord a) => SupersortStrat a
magicSuperStrat = mundaneSuperStrat