tree-monad 0.3 → 0.3.1

raw patch · 4 files changed

+58/−49 lines, 4 filesdep ~basesetup-changednew-uploader

Dependency ranges changed: base

Files

• CHANGELOG.md +5/−0
• Control/Monad/SearchTree.hs +28/−20
• Setup.hs +0/−2
• tree-monad.cabal +25/−27

@@ -0,0 +1,5 @@+# Revision history for tree-monad++## 0.3.1 -- 2020-10-23++* Add instances for `MonadFail`

@@ -1,28 +1,28 @@ {-# LANGUAGE Rank2Types #-}+ -- | -- Module      : Control.Monad.SearchTree -- Copyright   : Sebastian Fischer -- License     : BSD3--- --- Maintainer  : Sebastian Fischer (sebf@informatik.uni-kiel.de)+--+-- Maintainer  : Niels Bunkenburg (nbu@informatik.uni-kiel.de) -- Stability   : experimental -- Portability : portable--- +-- -- This Haskell library provides an implementation of the MonadPlus -- type class that represents the search space as a tree whose -- constructors represent mzero, return, and mplus.--- +-- -- Such a tree can be used to implement different search strategies, -- e.g., by using a queue. It can also be used as a basis for parallel -- search strategies that evaluate different parts of the search space -- concurrently.- module Control.Monad.SearchTree ( SearchTree(..), Search, searchTree ) where -import Control.Monad-import Control.Applicative+import           Control.Applicative+import           Control.Monad --- | +-- | -- The type @SearchTree a@ represents non-deterministic computations -- as a tree structure. data SearchTree a = None | One a | Choice (SearchTree a) (SearchTree a)@@ -35,34 +35,36 @@  instance Applicative SearchTree where   pure  = return+   (<*>) = ap  instance Alternative SearchTree where   empty = mzero+   (<|>) = mplus  instance Monad SearchTree where-  return = One+  return           = One -  None       >>= _ = None-  One x      >>= f = f x+  None >>= _       = None+  One x >>= f      = f x   Choice s t >>= f = Choice (s >>= f) (t >>= f) +instance MonadFail SearchTree where   fail _ = None  instance MonadPlus SearchTree where   mzero = None+   mplus = Choice  -- | -- Another search monad based on continuations that produce search -- trees.-newtype Search a = Search {--  -- | Passes a continuation to a monadic search action.-  search :: forall r . (a -> SearchTree r) -> SearchTree r-- }+newtype Search a = Search+  { -- | Passes a continuation to a monadic search action.+    search :: forall r. (a -> SearchTree r) -> SearchTree r+  }  -- | Computes the @SearchTree@ representation of a @Search@ action. searchTree :: Search a -> SearchTree a@@ -73,17 +75,23 @@  instance Applicative Search where   pure  = return+   (<*>) = ap  instance Alternative Search where   empty = mzero+   (<|>) = mplus  instance Monad Search where-  return x = Search ($x)-  a >>= f  = Search (\k -> search a (\x -> search (f x) k))-  fail _   = mzero+  return x = Search ($ x) +  a >>= f = Search (\k -> search a (\x -> search (f x) k))++instance MonadFail Search where+  fail _ = mzero+ instance MonadPlus Search where   mzero       = Search (const mzero)+   a `mplus` b = Search (\k -> search a k `mplus` search b k)

@@ -1,4 +1,2 @@ import Distribution.Simple- main = defaultMain-

@@ -1,31 +1,29 @@-Name:          tree-monad-Version:       0.3-Cabal-Version: >= 1.6-Synopsis:      Non-Determinism Monad for Tree Search-Description:   --  This Haskell library provides an implementation of the MonadPlus-  type class that represents the search space as a tree whose-  constructors represent mzero, return, and mplus.--Category:      Control, Monads-License:       BSD3-License-File:  LICENSE-Author:        Sebastian Fischer-Maintainer:    sebf@informatik.uni-kiel.de-Bug-Reports:   mailto:sebf@informatik.uni-kiel.de-Homepage:      http://sebfisch.github.com/tree-monad-Build-Type:    Simple-Stability:     experimental+cabal-version:       >=1.10 -Extra-Source-Files: README+name:                tree-monad+version:             0.3.1+synopsis:            Non-Determinism Monad for Tree Search+description:         This Haskell library provides an implementation of the+                     MonadPlus type class that represents the search space+                     as a tree whose constructors represent mzero, return,+                     and mplus.+homepage:            http://sebfisch.github.com/tree-monad+bug-reports:         https://github.com/nbun/tree-monad/issues+license:             BSD3+license-file:        LICENSE+author:              Sebastian Fischer+maintainer:          nbu@informatik.uni-kiel.de+category:            Control, Monads+build-type:          Simple+extra-source-files:  CHANGELOG.md, README -Library-  Build-Depends:    base >= 3 && < 5-  Exposed-Modules:  Control.Monad.SearchTree-  Ghc-Options:      -Wall-  Extensions:       Rank2Types+library+  exposed-modules:     Control.Monad.SearchTree+  other-extensions:    Rank2Types+  build-depends:       base >=4.13 && <4.15+  default-language:    Haskell2010+  ghc-options:         -Wall -Source-Repository head+source-repository head   type:     git-  location: git://github.com/sebfisch/tree-monad.git+  location: git://github.com/nbun/tree-monad.git