indexed-free 0.2.1 → 0.3.0

raw patch · 3 files changed

+53/−3 lines, 3 files

Files

• Control/Monad/Indexed/Free.hs +1/−1
• Control/MonadPlus/Indexed/Free.hs +50/−0
• indexed-free.cabal +2/−2

@@ -5,7 +5,7 @@ -- Copyright   :  (C) 2013 Fumiaki Kinoshita
 -- License     :  BSD-style (see the file LICENSE)
 --
--- Maintainer  :  Fumiaki Kinsohita <fumiexcel@gmail.com>
+-- Maintainer  :  Fumiaki Kinoshita <fumiexcel@gmail.com>
 -- Stability   :  provisional
 -- Portability :  non-portable
 --

@@ -0,0 +1,50 @@+{-# LANGUAGE GADTs, FlexibleInstances #-}
+module Control.MonadPlus.Indexed.Free (IxFree(..), module Control.Monad.Indexed.Free.Class) where
+
+import Control.Applicative
+import Control.Monad.Indexed
+import Control.Monad.Indexed.Free.Class
+
+data IxFree f i j x where
+    Pure :: a -> IxFree f i i a
+    Free :: f i j (IxFree f j k a) -> IxFree f i k a
+    Plus :: [IxFree f i j a] -> IxFree f i j a
+
+instance IxFunctor f => IxFunctor (IxFree f) where
+    imap f (Pure a) = Pure (f a)
+    imap f (Free w) = Free (imap (imap f) w)
+    imap f (Plus s) = Plus (map (imap f) s)
+
+instance IxFunctor f => IxPointed (IxFree f) where
+    ireturn = Pure
+
+instance IxFunctor f => IxApplicative (IxFree f) where
+    iap (Pure a) (Pure b) = Pure (a b)
+    iap (Pure a) (Free fb) = Free (imap a `imap` fb)
+    iap (Free fa) mb = Free $ imap (`iap` mb) fa
+
+instance IxFunctor f => IxMonadZero (IxFree f) where
+    imzero = Plus []
+
+instance IxFunctor f => IxMonad (IxFree f) where
+    ibind k (Pure a) = k a
+    ibind k (Free fm) = Free $ imap (ibind k) fm
+    ibind k (Plus m) = Plus (map (ibind k) m)
+
+instance IxFunctor f => IxMonadPlus (IxFree f) where
+  Plus [] `implus` r = r
+  l `implus` Plus [] = l
+  Plus as `implus` Plus bs = Plus (as ++ bs)
+  a `implus` b = Plus [a, b]
+
+instance IxFunctor f => Functor (IxFree f i i) where
+    fmap = imap
+
+instance IxFunctor f => Applicative (IxFree f i i) where
+    pure = ireturn
+    (<*>) = iap
+
+instance IxFunctor f => Monad (IxFree f i i) where
+    return = ireturn
+    (>>=) = (>>>=)
+

@@ -1,5 +1,5 @@ name:                indexed-free
-version:             0.2.1
+version:             0.3.0
 synopsis:            indexed monads for free
 description:         A free indexed monad
 homepage:            https://github.com/fumieval/indexed-free
@@ -17,6 +17,6 @@   location: https://github.com/fumieval/indexed-free.git
 
 library
-  exposed-modules:     Control.Monad.Indexed.Free, Control.Monad.Indexed.Free.Class, Control.Monad.Indexed.Trans.Free
+  exposed-modules:     Control.Monad.Indexed.Free, Control.Monad.Indexed.Free.Class, Control.Monad.Indexed.Trans.Free, Control.MonadPlus.Indexed.Free
 
   build-depends:       base ==4.*, indexed < 0.2