ivar-simple 0.3.2 → 0.3.3

raw patch · 7 files changed

+69/−35 lines, 7 filesdep ~basePVP: major bump suggested

API removals or changes: PVP suggests a major version bump

Dependency ranges changed: base

API changes (from Hackage documentation)

Files

• Changelog +8/−1
• LICENSE +1/−1
• Sample.hs +23/−0
• ivar-simple.cabal +8/−5
• src/Data/IVar/Simple.hs +14/−23
• src/Data/IVar/Simple/IChan.hs +13/−3
• src/Data/IVar/Simple/MIChan.hs +2/−2

@@ -1,5 +1,12 @@+0.3.3   (2020-10-06)+	* use only one `MVar` per `IVar` instead of two, taking advantage+	  of the fact that `readMVar` has been atomic since ghc 7.10+	* add `Eq` instance and `uncons` operation for `IChan`+	  (suggested by ski@Freenode)+ 0.3.2   (2015-10-29)-	* add Eq instances for `IVar` and `MIChan`+	* add `Eq` instances for `IVar` and `MIChan`+	  (suggested by nwf@Freenode)  0.3.1   (2015-07-02) 	* fix building with ghc 7.8

@@ -1,4 +1,4 @@-Copyright (c) 2008-2015 Bertram Felgenhauer+Copyright (c) 2008-2020 Bertram Felgenhauer  Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal

@@ -0,0 +1,23 @@+import qualified Data.IVar.Simple as IVar+import Control.Concurrent++main :: IO ()+main = do+    -- create new `IVar`+    iv <- IVar.new+    -- spawn a thread that reads the `IVar` and prints the value+    forkIO $ print (IVar.read iv)+    -- the spawned thread will sleep while the `IVar` is empty+    threadDelay 1000000+    -- tentatively read the `IVar` -- it's still empty+    IVar.tryRead iv >>= print+    -- write a value to the `IVar`+    IVar.write iv 42+    -- now the thread will be woken up and print "42"+    threadDelay 1000000+    -- tentatively read the `IVar` -- now it's full+    IVar.tryRead iv >>= print+    -- further writes fail: `tryWrite` returns `False`+    IVar.tryWrite iv 42 >>= print+    -- and `write` throws an exception+    IVar.write iv 42

@@ -1,8 +1,8 @@ name:          ivar-simple-version:       0.3.2+version:       0.3.3 category:      Concurrency stability:     experimental-copyright:     (c) 2008-2015 Bertram Felgenhauer+copyright:     (c) 2008-2020 Bertram Felgenhauer maintainer:    Bertram Felgenhauer <int-e@gmx.de> license:       MIT license-file:  LICENSE@@ -12,11 +12,12 @@   .   They can be read, an operation that will block until a value was written   to the variable. They can be written to exactly once.-cabal-version: >= 1.6+cabal-version: >= 1.10 build-type:    Simple extra-source-files:     README.md     Changelog+    Sample.hs  source-repository head   type:                 git@@ -30,7 +31,9 @@         Data.IVar.Simple         Data.IVar.Simple.IChan         Data.IVar.Simple.MIChan+    default-language:+        Haskell2010     build-depends:-        base >= 4 && < 5-    extensions:+        base >= 4.7 && < 5+    other-extensions:         DeriveDataTypeable

@@ -1,8 +1,8 @@-{-# LANGUAGE DeriveDataTypeable, CPP #-}+{-# LANGUAGE DeriveDataTypeable #-} -- | -- Module      : Data.IVar.Simple--- Copyright   : (c) 2008-2015 Bertram Felgenhauer--- License     : BSD3+-- Copyright   : (c) 2008-2020 Bertram Felgenhauer+-- License     : MIT -- -- Maintainer  : Bertram Felgenhauer <int-e@gmx.de> -- Stability   : experimental@@ -35,42 +35,41 @@ import Prelude hiding (read)  -- | A write-once (/immutable/) Variable-data IVar a = IVar (MVar ()) (MVar a) a+data IVar a = IVar (MVar a) a  instance Eq (IVar a) where-    IVar lock1 _ _ == IVar lock2 _ _ = lock1 == lock2+    IVar trans1 _ == IVar trans2 _ = trans1 == trans2     -- note: it would be possible to generalize the type to     -- eqIVar :: IVar a -> IVar b -> Bool  (but would that be useful?)  -- | Create a new, empty 'IVar'. new :: IO (IVar a) new = do-    lock <- newMVar ()     trans <- newEmptyMVar     let {-# NOINLINE value #-}-        value = unsafePerformIO $ takeMVar trans-    return (IVar lock trans value)+        value = unsafePerformIO $ readMVar trans+    return (IVar trans value)  -- | Create a new filled 'IVar'. -- -- This is slightly cheaper than creating a new 'IVar' and then writing to it. newFull :: a -> IO (IVar a) newFull value = do-    lock <- newEmptyMVar-    return (IVar lock (error "unused MVar") value)+    trans <- newMVar (error "unused value")+    return (IVar trans value)  -- | Returns the value of an 'IVar'. -- -- The evaluation will block until a value is written to the 'IVar' if it -- has no value yet. read :: IVar a -> a-read (IVar _ _ value) = value+read (IVar _ value) = value  -- | Try to read an 'IVar'. Returns 'Nothing' if it has no value yet. tryRead :: IVar a -> IO (Maybe a)-tryRead (IVar lock _ value) = do-    empty <- isEmptyMVar lock-    if empty then return (Just value) else return Nothing+tryRead (IVar trans value) = do+    empty <- isEmptyMVar trans+    if not empty then return (Just value) else return Nothing  -- | Writes a value to an 'IVar'. Raises a 'BlockedIndefinitelyOnIVar' -- exception if the variable already has a value.@@ -84,15 +83,7 @@ -- | Writes a value to an 'IVar'. Returns 'True' if successful, and -- 'False' otherwise. tryWrite :: IVar a -> a -> IO Bool-tryWrite (IVar lock trans _) value = block $ do-    a <- tryTakeMVar lock-    case a of-        Just _  -> putMVar trans value >> return True-        Nothing -> return False-#if __GLASGOW_HASKELL__ >= 708-  where-    block = mask_-#endif+tryWrite (IVar trans _) value = tryPutMVar trans value  -- | The thread has attempted to write to a full 'IVar'. data BlockedIndefinitelyOnIVar = BlockedIndefinitelyOnIVar

@@ -1,7 +1,7 @@ -- | -- Module      : Data.IVar.Simple.IChan--- Copyright   : (c) 2008-2012 Bertram Felgenhauer--- License     : BSD3+-- Copyright   : (c) 2008-2020 Bertram Felgenhauer+-- License     : MIT -- -- Maintainer  : Bertram Felgenhauer <int-e@gmx.de> -- Stability   : experimental@@ -19,6 +19,7 @@     IChan,     new,     read,+    uncons,     write,     tryWrite, ) where@@ -30,6 +31,7 @@  -- | A channel head newtype IChan a = IChan (IVar.IVar (a, IChan a))+    deriving Eq  -- | Create a new channel. new :: IO (IChan a)@@ -41,7 +43,15 @@ -- This is a pure computation. Forcing elements of the list may, however, -- block. read :: IChan a -> [a]-read (IChan as) = let (a, ic) = IVar.read as in a : read ic+read ic = let (a, ic') = uncons ic in a : read ic'++-- | Split channel into head and tail.+--+-- This is a pure operation, but it may block.+--+-- @since 0.3.3+uncons :: IChan a -> (a, IChan a)+uncons (IChan as) = IVar.read as  -- | Write a single value to the channel. --

@@ -1,7 +1,7 @@ -- | -- Module      : Data.IVar.Simple.MIChan--- Copyright   : (c) 2008-2012 Bertram Felgenhauer--- License     : BSD3+-- Copyright   : (c) 2008-2015 Bertram Felgenhauer+-- License     : MIT -- -- Maintainer  : Bertram Felgenhauer <int-e@gmx.de> -- Stability   : experimental