Split Character data type into Droid and Human

`Character` is now a synonym of the sum type of `Droid` and `Human`.

For now I don't see the need to implement GraphQL Schema interfaces with
type classes or lens. Plain Haskell ADTs should be good enough.
This commit is contained in:
Danny Navarro 2016-02-09 14:38:19 +01:00
parent df8e43c9aa
commit 70fbaf359e

View File

@ -131,7 +131,7 @@ query _ = empty
hero :: Alternative f => Resolver f
hero (InputList (InputScalar (ScalarInt ep) : inputFields)) =
withFields inputFields <$> getHero ep
hero (InputField fld) = characterOutput fld artoo
hero (InputField fld) = characterOutput fld $ Left artoo
hero _ = empty
human :: Alternative f => Resolver f
@ -171,98 +171,149 @@ withFields inputFields char =
-- ** Characters
data Character = Character
{ id_ :: ID
, name :: Text
, friends :: [ID]
, appearsIn :: [Int]
, homePlanet :: Text
data CharCommon = CharCommon
{ _id_ :: ID
, _name :: Text
, _friends :: [ID]
, _appearsIn :: [Int]
} deriving (Show)
luke :: Character
luke = Character
{ id_ = "1000"
, name = "Luke Skywalker"
, friends = ["1002","1003","2000","2001"]
, appearsIn = [4,5,6]
data Human = Human
{ _humanChar :: CharCommon
, homePlanet :: Text
}
data Droid = Droid
{ _droidChar :: CharCommon
, primaryFunction :: Text
}
type Character = Either Droid Human
-- I don't think this is cumbersome enough to make it worth using lens.
id_ :: Character -> ID
id_ (Left x) = _id_ . _droidChar $ x
id_ (Right x) = _id_ . _humanChar $ x
name :: Character -> Text
name (Left x) = _name . _droidChar $ x
name (Right x) = _name . _humanChar $ x
friends :: Character -> [ID]
friends (Left x) = _friends . _droidChar $ x
friends (Right x) = _friends . _humanChar $ x
appearsIn :: Character -> [Int]
appearsIn (Left x) = _appearsIn . _droidChar $ x
appearsIn (Right x) = _appearsIn . _humanChar $ x
luke :: Human
luke = Human
{ _humanChar = CharCommon
{ _id_ = "1000"
, _name = "Luke Skywalker"
, _friends = ["1002","1003","2000","2001"]
, _appearsIn = [4,5,6]
}
, homePlanet = "Tatoonie"
}
vader :: Character
vader = Character
{ id_ = "1001"
, name = "Darth Vader"
, friends = ["1004"]
, appearsIn = [4,5,6]
vader :: Human
vader = Human
{ _humanChar = CharCommon
{ _id_ = "1001"
, _name = "Darth Vader"
, _friends = ["1004"]
, _appearsIn = [4,5,6]
}
, homePlanet = "Tatooine"
}
han :: Character
han = Character
{ id_ = "1002"
, name = "Han Solo"
, friends = ["1000","1003","2001" ]
, appearsIn = [4,5,6]
han :: Human
han = Human
{ _humanChar = CharCommon
{ _id_ = "1002"
, _name = "Han Solo"
, _friends = ["1000","1003","2001" ]
, _appearsIn = [4,5,6]
}
, homePlanet = mempty
}
leia :: Character
leia = Character
{ id_ = "1003"
, name = "Leia Organa"
, friends = ["1000","1002","2000","2001"]
, appearsIn = [4,5,6]
leia :: Human
leia = Human
{ _humanChar = CharCommon
{ _id_ = "1003"
, _name = "Leia Organa"
, _friends = ["1000","1002","2000","2001"]
, _appearsIn = [4,5,6]
}
, homePlanet = "Alderaan"
}
tarkin :: Character
tarkin = Character
{ id_ = "1004"
, name = "Wilhuff Tarkin"
, friends = ["1001"]
, appearsIn = [4]
tarkin :: Human
tarkin = Human
{ _humanChar = CharCommon
{ _id_ = "1004"
, _name = "Wilhuff Tarkin"
, _friends = ["1001"]
, _appearsIn = [4]
}
, homePlanet = mempty
}
threepio :: Character
threepio = Character
{ id_ = "2000"
, name = "C-3PO"
, friends = ["1000","1002","1003","2001" ]
, appearsIn = [ 4, 5, 6 ]
, homePlanet = "Protocol"
threepio :: Droid
threepio = Droid
{ _droidChar = CharCommon
{ _id_ = "2000"
, _name = "C-3PO"
, _friends = ["1000","1002","1003","2001" ]
, _appearsIn = [ 4, 5, 6 ]
}
, primaryFunction = "Protocol"
}
artoo :: Character
artoo = Character
{ id_ = "2001"
, name = "R2-D2"
, friends = ["1000","1002","1003"]
, appearsIn = [4,5,6]
, homePlanet = "Astrometch"
artoo :: Droid
artoo = Droid
{ _droidChar = CharCommon
{ _id_ = "2001"
, _name = "R2-D2"
, _friends = ["1000","1002","1003"]
, _appearsIn = [4,5,6]
}
, primaryFunction = "Astrometch"
}
-- ** Helper functions
getHero :: Applicative f => Int -> f Character
getHero 5 = pure luke
getHero _ = pure artoo
getHero 5 = pure $ Right luke
getHero _ = pure $ Left artoo
getHeroIO :: Int -> IO Character
getHeroIO = getHero
getHuman :: Alternative f => ID -> f Character
getHuman "1000" = pure luke
getHuman "1001" = pure vader
getHuman "1002" = pure han
getHuman "1003" = pure leia
getHuman "1004" = pure tarkin
getHuman _ = empty
getHuman = fmap Right . getHuman'
getHuman' :: Alternative f => ID -> f Human
getHuman' "1000" = pure luke
getHuman' "1001" = pure vader
getHuman' "1002" = pure han
getHuman' "1003" = pure leia
getHuman' "1004" = pure tarkin
getHuman' _ = empty
getDroid :: Alternative f => ID -> f Character
getDroid "2000" = pure threepio
getDroid "2001" = pure artoo
getDroid _ = empty
getDroid = fmap Left . getDroid'
getDroid' :: Alternative f => ID -> f Droid
getDroid' "2000" = pure threepio
getDroid' "2001" = pure artoo
getDroid' _ = empty
getFriends :: Character -> [Character]
getFriends char = catMaybes $ liftA2 (<|>) getDroid getHuman <$> friends char