On 29 March 2006 11:00, Ross Paterson wrote:

On Tue, Mar 28, 2006 at 10:25:04AM +0100, Simon Marlow wrote:

...

On 28 March 2006 00:24, Ross Paterson wrote:

...

How about STM (minus retry/orElse) and TVars as the portable interface? They're trivial for a single-threaded implementation, and provide a comfortable interface for everyone.

It just occurred to me that STM isn't completely trivial in a single-threaded implementation, because exceptions have to abort a transaction in progress.

Almost trivial, though:

import Prelude hiding (catch) import Control.Exception import Data.IORef

-- The reference contains a rollback action to be executed on newtype STM a = STM (IORef (IO ()) -> IO a)

very clever ;-) Simon