random-extras (empty) → 0.1

raw patch · 4 files changed

+186/−0 lines, 4 filesdep +MonadRandomdep +basedep +containerssetup-changed

Dependencies added: MonadRandom, base, containers, monad-loops

Files

Control/Monad/Random/Extras.hs +87/−0
LICENSE +30/−0
Setup.hs +2/−0
random-extras.cabal +67/−0

+ Control/Monad/Random/Extras.hs view

@@ -0,0 +1,87 @@+{- |+Module       : Control.Monad.Random.Extras+Copyright    : 2010 Aristid Breitkreuz+License      : BSD3+Stability    : experimental+Portability  : portable++Additional monadic random functions, based on 'MonadRandom'.++-}+++module Control.Monad.Random.Extras+(+  -- * Random functions+  -- ** Shuffling+  shuffle+, shuffleSeq+  -- ** Choice+, choiceExtract+, choiceExtractSeq+, choice+, choiceSeq+)+where++import Control.Monad (MonadPlus, liftM)+import Control.Monad.Loops (unfoldrM')+import Control.Monad.Random (MonadRandom, getRandomR)+import qualified Data.Sequence as Seq+import Data.Sequence ((><), ViewL((:<)))++extract :: [a] -> Int -> Maybe (a, [a])+extract s i | null r    = Nothing+            | otherwise = Just (b, a ++ c)+    where (a, r) = splitAt i s+          (b : c) = r++extractSeq :: Seq.Seq a -> Int -> Maybe (a, Seq.Seq a)+extractSeq s i | Seq.null r = Nothing+               | otherwise  = Just (b, a >< c)+    where (a, r) = Seq.splitAt i s +          (b :< c) = Seq.viewl r++-- | Shuffle a list randomly. The method is based on Oleg Kiselyov's +-- /perfect shuffle/ <http://okmij.org/ftp/Haskell/perfect-shuffle.txt>,+-- but much simpler because it uses existing data structures. The efficiency+-- of both methods should be comparable.+--+-- Complexity: O(n * log n)+shuffle :: (MonadRandom m) => [a] -> m [a]+shuffle = shuffleSeq . Seq.fromList++-- | Shuffle a sequence randomly. This is being used by 'shuffle',+-- so it logically uses the same method.+--+-- Complexity: O(n * log n)+shuffleSeq :: (MonadRandom m, MonadPlus f) => Seq.Seq a -> m (f a)+shuffleSeq = unfoldrM' choiceExtractSeq++-- | Randomly choose and extract an element from a list.+--+-- Complexity: O(n)+choiceExtract :: (MonadRandom m) => [a] -> m (Maybe (a, [a]))+choiceExtract [] = return Nothing+choiceExtract xs = extract xs `liftM` getRandomR (0, length xs - 1)+                    +-- | Randomly choose and extract an element from a sequence.+--+-- Complexity: O(log n)+choiceExtractSeq :: (MonadRandom m) => Seq.Seq a -> m (Maybe (a, Seq.Seq a))+choiceExtractSeq s | Seq.null s = return Nothing+                   | otherwise  = extractSeq s `liftM` getRandomR (0, Seq.length s - 1)++-- | Select a random element from a list.+--+-- Complexity: O(n).+choice :: (MonadRandom m) => [a] -> m a+choice [] = error "Control.Monad.Random.Extras.choice: empty list"+choice xs = (xs !!) `liftM` getRandomR (0, length xs - 1)++-- | Select a random element from a sequence.+--+-- Complexity: O(log n).+choiceSeq :: (MonadRandom m) => Seq.Seq a -> m a+choiceSeq s | Seq.null s = error "Control.Monad.Random.Extras.choiceSeq: empty sequence"+            | otherwise  = Seq.index s `liftM` getRandomR (0, Seq.length s - 1)

+ LICENSE view

@@ -0,0 +1,30 @@+Copyright (c) 2010, Aristid Breitkreuz++All rights reserved.++Redistribution and use in source and binary forms, with or without+modification, are permitted provided that the following conditions are met:++    * Redistributions of source code must retain the above copyright+      notice, this list of conditions and the following disclaimer.++    * Redistributions in binary form must reproduce the above+      copyright notice, this list of conditions and the following+      disclaimer in the documentation and/or other materials provided+      with the distribution.++    * Neither the name of Aristid Breitkreuz nor the names of other+      contributors may be used to endorse or promote products derived+      from this software without specific prior written permission.++THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS+"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT+LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR+A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT+OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,+SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT+LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,+DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY+THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT+(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE+OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

+ Setup.hs view

@@ -0,0 +1,2 @@+import Distribution.Simple+main = defaultMain

+ random-extras.cabal view

@@ -0,0 +1,67 @@+-- random-extras.cabal auto-generated by cabal init. For additional+-- options, see+-- http://www.haskell.org/cabal/release/cabal-latest/doc/users-guide/authors.html#pkg-descr.+-- The name of the package.+Name:                random-extras++-- The package version. See the Haskell package versioning policy+-- (http://www.haskell.org/haskellwiki/Package_versioning_policy) for+-- standards guiding when and how versions should be incremented.+Version:             0.1++-- A short (one-line) description of the package.+Synopsis:            Additional functions for random values.++-- A longer description of the package.+Description:         Additional functions for random values, based on MonadRandom. Inspired by random-shuffle.++-- URL for the project homepage or repository.+Homepage:            http://github.com/aristidb/random-extras++-- The license under which the package is released.+License:             BSD3++-- The file containing the license text.+License-file:        LICENSE++-- The package author(s).+Author:              Aristid Breitkreuz++-- An email address to which users can send suggestions, bug reports,+-- and patches.+Maintainer:          aristidb@googlemail.com++-- A copyright notice.+-- Copyright:           ++Category:            Control++Build-type:          Simple++-- Extra files to be distributed with the package, such as examples or+-- a README.+-- Extra-source-files:  ++-- Constraint on the version of Cabal needed to build this package.+Cabal-version:       >=1.8+++Library+  -- Modules exported by the library.+  Exposed-modules:+        Control.Monad.Random.Extras+  +  -- Packages needed in order to build this package.+  Build-depends:+        base >=4 && <5,+        containers ==0.3.*,+        MonadRandom ==0.1.*,+        monad-loops ==0.3.1.*+  +  -- Modules not exported by this package.+  -- Other-modules:       +  +  -- Extra tools (e.g. alex, hsc2hs, ...) needed to build the source.+  -- Build-tools:         +  +  GHC-Options: -Wall