Breaking out Data.Inject

Author: ethul

README.md

@@ -84,6 +84,8 @@
 
     goMC :: forall f m a. (Monad m) => Natural f m -> FreeC f a -> m a
 
+    injC :: forall f g a. (Inject f g) => FreeC f a -> FreeC g a
+
     iterM :: forall f m a. (Functor f, Monad m) => (forall a. f (m a) -> m a) -> Free f a -> m a
 
     liftF :: forall f m a. (Functor f, Monad m, MonadFree f m) => f a -> m a
@@ -162,29 +164,6 @@
     lowerCoyoneda :: forall f a. (Functor f) => Coyoneda f a -> f a
 
 
-## Module Data.Inject
-
-### Type Classes
-
-    class Inject f g where
-      inj :: forall a. f a -> g a
-      prj :: forall a. g a -> Maybe (f a)
-
-
-### Type Class Instances
-
-    instance injectLeft :: Inject f (Coproduct f g)
-
-    instance injectReflexive :: Inject f f
-
-    instance injectRight :: (Inject f g) => Inject f (Coproduct h g)
-
-
-### Values
-
-    injC :: forall f g a. (Inject f g) => FreeC f a -> FreeC g a
-
-
 ## Module Data.Yoneda
 
 ### Types

bower.json

@@ -30,6 +30,7 @@
     "purescript-transformers": "~0.3.0",
     "purescript-lazy": "~0.1.1",
     "purescript-foldable-traversable": "~0.1.4",
-    "purescript-coproducts": "~0.1.0"
+    "purescript-coproducts": "~0.1.0",
+    "purescript-inject": "~0.0.2"
   }
 }

examples/TeletypeCoproduct.purs

@@ -3,9 +3,9 @@ module TeletypeCoproduct where
 import Control.Apply ((*>))
 import Control.Alt ((<|>))
 import Control.Monad.Eff (Eff())
-import Control.Monad.Free (FreeC(), liftFC, goEffC)
+import Control.Monad.Free (FreeC(), liftFC, injC, goEffC)
 import Data.Coyoneda (Natural())
-import Data.Inject (prj, injC)
+import Data.Inject (prj)
 import Data.Functor.Coproduct (Coproduct())
 import Data.Maybe.Unsafe (fromJust)
 import Debug.Trace (Trace(), trace)

src/Control/Monad/Free.purs

@@ -4,7 +4,7 @@ module Control.Monad.Free
   , MonadFree, wrap
   , liftF, liftFC
   , pureF, pureFC
-  , mapF
+  , mapF, injC
   , iterM
   , goM, goMC
   , go
@@ -16,6 +16,7 @@ import Control.Monad.Eff
 import Data.Coyoneda
 import Data.Either
 import Data.Function
+import Data.Inject (Inject, inj)
 
 data Free f a = Pure a
               | Free (f (Free f a))
@@ -65,6 +66,9 @@ pureFC = liftFC <<< pure
 mapF :: forall f g a. (Functor f, Functor g) => Natural f g -> Free f a -> Free g a
 mapF t fa = either (\s -> Free <<< t $ mapF t <$> s) Pure (resume fa)
 
+injC :: forall f g a. (Inject f g) => FreeC f a -> FreeC g a
+injC = mapF (liftCoyonedaT inj)
+
 -- Note: can blow the stack!
 iterM :: forall f m a. (Functor f, Monad m) => (forall a. f (m a) -> m a) -> Free f a -> m a
 iterM _ (Pure a) = return a