Safe Haskell	None
Language	Haskell2010

Mikan.Utils.Favorites

Contents

Comparison
Insertion
Combination
Conversions

Description

Maintaining a list of favorites of some partially ordered type. Only the best elements are kept.

To avoid name clashes, import this module qualified, as in

import Mikan.Utils.Favorites (Favorites)
import Mikan.Utils.Favorites qualified as Fav

Synopsis

data Favorites a
data CompareResult a
- = Dominates {
  - dominated :: [a]
  - notDominated :: [a]
  }
- | IsDominated {
  - dominator :: a
  }
compareWithFavorites :: PartialOrd a => a -> Favorites a -> CompareResult a
compareFavorites :: PartialOrd a => Favorites a -> Favorites a -> (Favorites a, Favorites a)
insertCompared :: a -> Favorites a -> CompareResult a -> Favorites a
insert :: PartialOrd a => a -> Favorites a -> Favorites a
unionCompared :: (Favorites a, Favorites a) -> Favorites a
union :: PartialOrd a => Favorites a -> Favorites a -> Favorites a
toList :: Favorites a -> [a]
fromList :: PartialOrd a => [a] -> Favorites a

Documentation

data Favorites a Source #

A list of incomparable favorites.

Instances

Instances details

Functor Favorites Source #
Instance details Defined in Mikan.Utils.Favorites Methods fmap :: (a -> b) -> Favorites a -> Favorites b # (<$) :: a -> Favorites b -> Favorites a #
Foldable Favorites Source #
Instance details Defined in Mikan.Utils.Favorites Methods fold :: Monoid m => Favorites m -> m # foldMap :: Monoid m => (a -> m) -> Favorites a -> m # foldMap' :: Monoid m => (a -> m) -> Favorites a -> m # foldr :: (a -> b -> b) -> b -> Favorites a -> b # foldr' :: (a -> b -> b) -> b -> Favorites a -> b # foldl :: (b -> a -> b) -> b -> Favorites a -> b # foldl' :: (b -> a -> b) -> b -> Favorites a -> b # foldr1 :: (a -> a -> a) -> Favorites a -> a # foldl1 :: (a -> a -> a) -> Favorites a -> a # toList :: Favorites a -> [a] # null :: Favorites a -> Bool # length :: Favorites a -> Int # elem :: Eq a => a -> Favorites a -> Bool # maximum :: Ord a => Favorites a -> a # minimum :: Ord a => Favorites a -> a # sum :: Num a => Favorites a -> a # product :: Num a => Favorites a -> a #
Singleton a (Favorites a) Source #
Instance details Defined in Mikan.Utils.Favorites Methods singleton :: a -> Favorites a Source #
Null (Favorites a) Source #
Instance details Defined in Mikan.Utils.Favorites Methods empty :: Favorites a Source # null :: Favorites a -> Bool Source #
PartialOrd a => Monoid (Favorites a) Source #
Instance details Defined in Mikan.Utils.Favorites Methods mempty :: Favorites a # mappend :: Favorites a -> Favorites a -> Favorites a # mconcat :: [Favorites a] -> Favorites a #
PartialOrd a => Semigroup (Favorites a) Source #	`Favorites` forms a `Monoid` under `empty` and `union`.
Instance details Defined in Mikan.Utils.Favorites Methods (<>) :: Favorites a -> Favorites a -> Favorites a # sconcat :: NonEmpty (Favorites a) -> Favorites a # stimes :: Integral b => b -> Favorites a -> Favorites a #
Show a => Show (Favorites a) Source #
Instance details Defined in Mikan.Utils.Favorites Methods showsPrec :: Int -> Favorites a -> ShowS # show :: Favorites a -> String # showList :: [Favorites a] -> ShowS #
Ord a => Eq (Favorites a) Source #	Equality checking is a bit expensive, since we need to sort! Maybe use a `Set` of favorites in the first place?
Instance details Defined in Mikan.Utils.Favorites Methods (==) :: Favorites a -> Favorites a -> Bool # (/=) :: Favorites a -> Favorites a -> Bool #

Comparison

data CompareResult a Source #

Result of comparing a candidate with the current favorites.

Constructors

Dominates	Great, you are dominating a possibly (empty list of favorites) but there is also a rest that is not dominated. If `null dominated`, then `notDominated` is necessarily the complete list of favorites.
Fields dominated :: [a] notDominated :: [a]
IsDominated	Sorry, but you are dominated by that favorite.
Fields dominator :: a

compareWithFavorites :: PartialOrd a => a -> Favorites a -> CompareResult a Source #

Gosh, got some pretty a here, compare with my current favorites! Discard it if there is already one that is better or equal. (Skewed conservatively: faithful to the old favorites.) If there is no match for it, add it, and dispose of all that are worse than a.

We require a partial ordering. Less is better! (Maybe paradoxically.)

compareFavorites :: PartialOrd a => Favorites a -> Favorites a -> (Favorites a, Favorites a) Source #

Compare a new set of favorites to an old one and discard the new favorites that are dominated by the old ones and vice verse. (Skewed conservatively: faithful to the old favorites.)

compareFavorites new old = (new', old')

Insertion

insertCompared :: a -> Favorites a -> CompareResult a -> Favorites a Source #

After comparing, do the actual insertion.

insert :: PartialOrd a => a -> Favorites a -> Favorites a Source #

Compare, then insert accordingly. insert a l = insertCompared a l (compareWithFavorites a l)

Combination

unionCompared :: (Favorites a, Favorites a) -> Favorites a Source #

union :: PartialOrd a => Favorites a -> Favorites a -> Favorites a Source #

Insert all the favorites from the first list into the second.

Conversions

toList :: Favorites a -> [a] Source #

fromList :: PartialOrd a => [a] -> Favorites a Source #

Construct favorites from elements of a partial order. The result depends on the order of the list if it contains equal elements, since earlier seen elements are favored over later seen equals. The first element of the list is seen first.