Mercurial > hg > Members > atton > delta_monad

comparison similer.hs @ 3:3c5fbce357af

Find changesets by keywords (author, files, the commit message), revision number or hash, or revset expression.
Define >>= for Similer
author Yasutaka Higa <e115763@ie.u-ryukyu.ac.jp>
date Sun, 31 Aug 2014 19:21:42 +0900
parents a5210ec1e41b
children 66609010d477
comparison
equal deleted inserted replaced
2:a5210ec1e41b 3:3c5fbce357af
1 {-# LANGUAGE FlexibleContexts #-} 1 {-# LANGUAGE UndecidableInstances #-}
2 data Similer a b = Similer a (a -> b) b 2 data Similer a b = Similer a (a -> b) b
3 3
4 instance Functor (Similer a) where 4 instance Functor (Similer a) where
5 fmap g (Similer a f b) = Similer a (g . f) $ g b 5 fmap g (Similer a f b) = Similer a (g . f) $ g b
6 6
7 same :: (Eq a) => Similer a b -> Similer a b -> Bool
8 same (Similer a _ _ ) (Similer b _ _) = a == b
9
7 eta :: a -> Similer a a 10 eta :: a -> Similer a a
8 eta a = Similer a id a 11 eta a = Similer a id a
9 12
10 --mu :: (Eq (Similer b (b -> c) c)) => Similer a (a -> (Similer b (b -> c) c)) (Similer b (b -> c) c) -> Similer b (b -> c) c 13 mu :: (Eq b) => Similer a (Similer b c) -> Similer b c
11 mu :: (Eq (Similer b c)) => Similer a (Similer b c) -> Similer b c 14 mu (Similer a f b) = if (same (f a) b) then b else undefined
12 mu (Similer a f b) = if ((f a) == b) then b else undefined 15
16 instance (Eq a) => Monad (Similer a) where
17 --return x = Similer x id x
18 s >>= f = mu (fmap f s)