{-# LANGUAGE MultiParamTypeClasses, FunctionalDependencies, FlexibleInstances, UndecidableInstances, RankNTypes, FlexibleContexts, LambdaCase, ScopedTypeVariables, Safe #-} {- This module is part of Chatty. Copyleft (c) 2014 Marvin Cohrs All wrongs reversed. Sharing is an act of love, not crime. Please share Chatty with everyone you like. Chatty is free software: you can redistribute it and/or modify it under the terms of the GNU Affero General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version. Chatty is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Affero General Public License for more details. You should have received a copy of the GNU Affero General Public License along with Chatty. If not, see <http://www.gnu.org/licenses/>. -} module Data.Chatty.Hetero where infixr 9 :-: -- | The Cons type for a heterogenous list data Cons a b = (:-:) a b -- | The empty list data Nil = Nil -- | Typeclass for appending one heterogenous list to another one class Append a b ab | a b -> ab where tappend :: a -> b -> ab instance Append Nil b b where tappend :: Nil -> b -> b tappend Nil Nil b b = b b instance Append b c bc => Append (Cons a b) c (Cons a bc) where tappend :: Cons a b -> c -> Cons a bc tappend (a a :-: b b) c c = a a a -> bc -> Cons a bc forall a b. a -> b -> Cons a b :-: b -> c -> bc forall a b ab. Append a b ab => a -> b -> ab tappend b b c c -- | Typeclass for wrapping a heterogenous list into a Maybe on demand class IntoMaybe a ar | a -> ar where tjust :: a -> ar tnothing :: a -> ar instance IntoMaybe Nil Nil where tjust :: Nil -> Nil tjust Nil Nil = Nil Nil tnothing :: Nil -> Nil tnothing Nil a = Nil Nil instance IntoMaybe (Cons a as) (Cons (Maybe (Cons a as)) Nil) where tjust :: Cons a as -> Cons (Maybe (Cons a as)) Nil tjust Cons a as a = Cons a as -> Maybe (Cons a as) forall a. a -> Maybe a Just Cons a as a Maybe (Cons a as) -> Nil -> Cons (Maybe (Cons a as)) Nil forall a b. a -> b -> Cons a b :-: Nil Nil tnothing :: Cons a as -> Cons (Maybe (Cons a as)) Nil tnothing Cons a as a = Maybe (Cons a as) forall a. Maybe a Nothing Maybe (Cons a as) -> Nil -> Cons (Maybe (Cons a as)) Nil forall a b. a -> b -> Cons a b :-: Nil Nil -- | Typeclass for everything that may be converted to a tuple class Tuplify l t | l -> t where tuplify :: l -> t instance Tuplify Nil () where tuplify :: Nil -> () tuplify Nil Nil = () instance Tuplify a ar => Tuplify (Cons a Nil) ar where tuplify :: Cons a Nil -> ar tuplify (a a :-: Nil Nil) = a -> ar forall l t. Tuplify l t => l -> t tuplify a a instance (Tuplify a ar, Tuplify b br) => Tuplify (Cons a (Cons b Nil)) (ar,br) where tuplify :: Cons a (Cons b Nil) -> (ar, br) tuplify (a a :-: b b :-: Nil Nil) = (a -> ar forall l t. Tuplify l t => l -> t tuplify a a, b -> br forall l t. Tuplify l t => l -> t tuplify b b) instance (Tuplify a ar, Tuplify b br, Tuplify c cr) => Tuplify (Cons a (Cons b (Cons c Nil))) (ar,br,cr) where tuplify :: Cons a (Cons b (Cons c Nil)) -> (ar, br, cr) tuplify (a a :-: b b :-: c c :-: Nil Nil) = (a -> ar forall l t. Tuplify l t => l -> t tuplify a a, b -> br forall l t. Tuplify l t => l -> t tuplify b b, c -> cr forall l t. Tuplify l t => l -> t tuplify c c) instance (Tuplify a ar, Tuplify b br, Tuplify c cr, Tuplify d dr) => Tuplify (Cons a (Cons b (Cons c (Cons d Nil)))) (ar,br,cr,dr) where tuplify :: Cons a (Cons b (Cons c (Cons d Nil))) -> (ar, br, cr, dr) tuplify (a a :-: b b :-: c c :-: d d :-: Nil Nil) = (a -> ar forall l t. Tuplify l t => l -> t tuplify a a, b -> br forall l t. Tuplify l t => l -> t tuplify b b,c -> cr forall l t. Tuplify l t => l -> t tuplify c c,d -> dr forall l t. Tuplify l t => l -> t tuplify d d) instance (Tuplify a ar, Tuplify b br, Tuplify c cr, Tuplify d dr, Tuplify e er) => Tuplify (Cons a (Cons b (Cons c (Cons d (Cons e Nil))))) (ar,br,cr,dr,er) where tuplify :: Cons a (Cons b (Cons c (Cons d (Cons e Nil)))) -> (ar, br, cr, dr, er) tuplify (a a :-: b b :-: c c :-: d d :-: e e :-: Nil Nil) = (a -> ar forall l t. Tuplify l t => l -> t tuplify a a,b -> br forall l t. Tuplify l t => l -> t tuplify b b,c -> cr forall l t. Tuplify l t => l -> t tuplify c c,d -> dr forall l t. Tuplify l t => l -> t tuplify d d,e -> er forall l t. Tuplify l t => l -> t tuplify e e) instance (Tuplify a ar, Tuplify b br, Tuplify c cr, Tuplify d dr, Tuplify e er, Tuplify f fr) => Tuplify (Cons a (Cons b (Cons c (Cons d (Cons e (Cons f Nil)))))) (ar,br,cr,dr,er,fr) where tuplify :: Cons a (Cons b (Cons c (Cons d (Cons e (Cons f Nil))))) -> (ar, br, cr, dr, er, fr) tuplify (a a :-: b b :-: c c :-: d d :-: e e :-: f f :-: Nil Nil) = (a -> ar forall l t. Tuplify l t => l -> t tuplify a a,b -> br forall l t. Tuplify l t => l -> t tuplify b b,c -> cr forall l t. Tuplify l t => l -> t tuplify c c,d -> dr forall l t. Tuplify l t => l -> t tuplify d d,e -> er forall l t. Tuplify l t => l -> t tuplify e e,f -> fr forall l t. Tuplify l t => l -> t tuplify f f) instance Tuplify Int Int where tuplify :: Int -> Int tuplify = Int -> Int forall a. a -> a id instance Tuplify Char Char where tuplify :: Char -> Char tuplify = Char -> Char forall a. a -> a id instance Tuplify a ar => Tuplify [a] [ar] where tuplify :: [a] -> [ar] tuplify = (a -> ar) -> [a] -> [ar] forall a b. (a -> b) -> [a] -> [b] map a -> ar forall l t. Tuplify l t => l -> t tuplify instance Tuplify a ar => Tuplify (Maybe a) (Maybe ar) where tuplify :: Maybe a -> Maybe ar tuplify = (a -> ar) -> Maybe a -> Maybe ar forall (f :: * -> *) a b. Functor f => (a -> b) -> f a -> f b fmap a -> ar forall l t. Tuplify l t => l -> t tuplify data Titled a = Titled String a instance Tuplify a ar => Tuplify (Titled a) ar where tuplify :: Titled a -> ar tuplify (Titled String _ a a) = a -> ar forall l t. Tuplify l t => l -> t tuplify a a