hmmm .. Jeremy .... http://notes-on-haskell.blogspot.com/2007/03/design-patterns-in-haskell-bracket.html....
thx, vasili On Wed, Aug 6, 2008 at 2:25 AM, Jeremy Shaw <[EMAIL PROTECTED]> wrote: > At Wed, 6 Aug 2008 00:43:55 -0500, > Galchin, Vasili wrote: > > > > [1 <multipart/alternative (7bit)>] > > [1.1 <text/plain; ISO-8859-1 (7bit)>] > > Hello, > > > > 1) Is there a common assumed semantics across all of the Haskell > "with" > > things? withString? withData? > > A vague semantic is that some resource is acquired, used, and then > released. > > > 2) If the answer to 1) is yes, then does this imply some kind of > > polymorphism? Couldn't "with" be "reduced" to a higher order function > then > > ?? > > I think Control.Exception.bracket is used to implement many, but not > all, of the with* functions. > > > newThing :: IO a > > newThing = ... > > > destroyThing :: a -> IO b > > destroyThing ... > > > withThing :: (Thing -> IO a) -> IO a > > withThing useThing = bracket newThing destroyThing useThing > > I have not fully answered either of your questions, but hopefully this > is a start. > > j. >
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