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Diffstat (limited to 'Com/Simatime/Go.hs')
-rw-r--r-- | Com/Simatime/Go.hs | 106 |
1 files changed, 0 insertions, 106 deletions
diff --git a/Com/Simatime/Go.hs b/Com/Simatime/Go.hs deleted file mode 100644 index 01555f3..0000000 --- a/Com/Simatime/Go.hs +++ /dev/null @@ -1,106 +0,0 @@ -{- | An EDSL to make working with concurrent in-process code a bit easier - to read. - -This module is expected to be imported qualified as `Go`. Inspired by -Golang and Clojure's core.async. - -$example --} -{-# LANGUAGE NoImplicitPrelude #-} -{-# LANGUAGE OverloadedStrings #-} -module Com.Simatime.Go - ( - -- * Running and forking - fork - -- * Channels - , Channel - , chan - , read - , write - , mult - , tap - ) -where - -import Alpha hiding ( read ) -import qualified Control.Concurrent as Concurrent -import qualified Control.Concurrent.Chan.Unagi.Bounded - as Chan -import qualified Data.Aeson as Aeson -import qualified System.IO.Unsafe as Unsafe - --- | A standard channel. -data Channel a = Channel - { _in :: Chan.InChan a - , _out :: Chan.OutChan a - , _size :: Int - } - -instance Aeson.ToJSON (Channel a) where - toJSON c = Aeson.String ("#<channel " <> len c <> ">" :: Text) - where len = show . Unsafe.unsafePerformIO . Chan.estimatedLength . _in - --- | Starts a background process. -fork :: IO () -> IO Concurrent.ThreadId -fork = Concurrent.forkIO - --- | Make a new channel. -chan :: Int -> IO (Channel a) -chan n = do - (i, o) <- Chan.newChan n - return <| Channel i o n - --- | A channel for broadcasting to multiple consumers. See 'mult'. -type Mult a = Chan.OutChan a - --- | Duplicates a channel, but then anything written to the source will --- be available to both. This is like Clojure's `core.async/mult` -mult :: Channel a -> IO (Mult a) -mult = Chan.dupChan . _in - --- | Read a value from a 'Mult'. This is like Clojure's `core.async/tap`. --- --- You can use this to read from a channel in a background process, e.g.: --- --- >>> c <- Go.chan --- >>> Go.fork . forever <| Go.mult c >>= Go.tap >>= print -tap :: Mult a -> IO a -tap = Chan.readChan - --- | Take from a channel. Blocks until a value is received. -read :: Channel a -> IO a -read = Chan.readChan . _out - --- | Write to a channel. Blocks if the channel is full. -write :: Channel a -> a -> IO Bool -write = Chan.tryWriteChan . _in - -{- $example - -A simple example from ghci: - ->>> import qualified Com.Simatime.Go as Go ->>> c <- Go.chan :: IO (Go.Channel Text) ->>> Go.write c "test" ->>> Go.read c -"test" - -An example with tap and mult: - ->>> c <- Go.chan :: IO (Go.Channel Text) ->>> Go.write c "hi" ->>> Go.read c -"hi" ->>> Go.fork ->>> Go.fork $ forever $ Go.mult c >>= Go.tap >>= \t -> print ("one: " <> t) -ThreadId 810 ->>> Go.fork $ forever $ Go.mult c >>= Go.tap >>= \t -> print ("two: " <> t) -ThreadId 825 ->>> Go.write c "test" -"two: t"eosnte": - test" - -The text is garbled because the actions are happening concurrently and -trying to serialize to write the output, but you get the idea. - --} |