tree-monad 0.3.1 → 0.3.2

raw patch · 2 files changed

+21/−8 lines, 2 filesdep ~base

Dependency ranges changed: base

Files

• Control/Monad/SearchTree.hs +19/−6
• tree-monad.cabal +2/−2

@@ -21,6 +21,7 @@  import           Control.Applicative import           Control.Monad+import           Control.Monad.Fix  -- | -- The type @SearchTree a@ represents non-deterministic computations@@ -34,7 +35,7 @@   fmap f (Choice s t) = Choice (fmap f s) (fmap f t)  instance Applicative SearchTree where-  pure  = return+  pure  = One    (<*>) = ap @@ -44,8 +45,6 @@   (<|>) = mplus  instance Monad SearchTree where-  return           = One-   None >>= _       = None   One x >>= f      = f x   Choice s t >>= f = Choice (s >>= f) (t >>= f)@@ -58,6 +57,19 @@    mplus = Choice +instance MonadFix SearchTree where+  mfix f = case fix (f . unOne) of+             None       -> None+             One x      -> One x+             Choice _ _ -> Choice (mfix (leftChoice . f)) (mfix (rightChoice . f))+    where+      unOne (One x) = x+      unOne _       = error "mfix SearchTree: not One"+      leftChoice (Choice s _) = s+      leftChoice _            = error "mfix SearchTree: not Choice"+      rightChoice (Choice _ t) = t+      rightChoice _            = error "mfix SearchTree: not Choice"+ -- | -- Another search monad based on continuations that produce search -- trees.@@ -74,7 +86,7 @@   fmap f a = Search (\k -> search a (k . f))  instance Applicative Search where-  pure  = return+  pure x = Search ($ x)    (<*>) = ap @@ -84,8 +96,6 @@   (<|>) = mplus  instance Monad Search where-  return x = Search ($ x)-   a >>= f = Search (\k -> search a (\x -> search (f x) k))  instance MonadFail Search where@@ -95,3 +105,6 @@   mzero       = Search (const mzero)    a `mplus` b = Search (\k -> search a k `mplus` search b k)++instance MonadFix Search where+  mfix f = Search (\k -> mfix (searchTree . f) >>= k)

@@ -1,7 +1,7 @@ cabal-version:       >=1.10  name:                tree-monad-version:             0.3.1+version:             0.3.2 synopsis:            Non-Determinism Monad for Tree Search description:         This Haskell library provides an implementation of the                      MonadPlus type class that represents the search space@@ -20,7 +20,7 @@ library   exposed-modules:     Control.Monad.SearchTree   other-extensions:    Rank2Types-  build-depends:       base >=4.13 && <4.15+  build-depends:       base >=4.13 && <4.16.3   default-language:    Haskell2010   ghc-options:         -Wall