Re: [Haskell] Re: ANNOUNCE: HNOP 0.1
I do think that refactoring this to a library would be a much better idea. That way we can see how this scales to multithreaded applications. Will there be a HNOP 2.0 that takes advantage of such fancy features such as MPTC or FD? It would be interesting to see how this problem reduces when one uses these advanced Haskell features. Perhaps as showcase to show that MPTC and FD definitely improve code-readability and design-abstraction/ Cheers,Christophe (vincenz)On 6/30/06, Ashley Yakeley <[EMAIL PROTECTED]> wrote: In article<[EMAIL PROTECTED]>, "Bayley, Alistair" < [EMAIL PROTECTED]> wrote:> Cool, that's awesome. But I don't see any Haddock docs? Or a Cabal> Setup.hs? Would it be much trouble to add them? Bear in mind HNOP compiles just to an executable file, so it doesn'treally have a Haskell API.One interesting line of development would be to spin off the corefunctionality into a separate library, to provide no-op services to other Haskell applications. I'm thinking something like this: noop :: IO () -- generalise to other Monads?This would actually not be too hard to write, given my existing work,and then of course the executable would simply be a thin wrapper. --Ashley YakeleySeattle WA___Haskell mailing listHaskell@haskell.org http://www.haskell.org/mailman/listinfo/haskell ___ Haskell mailing list Haskell@haskell.org http://www.haskell.org/mailman/listinfo/haskell
Re: [Haskell] (.) . (.)
Hello, I think you look at the (.) . (.) as all being c's in the wrong way. You have to consider what will evaluate first (syntactical priority rules). Anyways the simplest case that this is equivalent can be seen here: 22:33 < vincenz> @pl \f g a b -> f (g a b) 22:33 < lambdabot> (.) . (.) Writing it explicilty: (.) f g a = f (g a) so we get (.) . (.) = \f -> (.) ((.) f) (.) . (.) f = (.) ((.) f) (.) . (.) f g = (.) ((.) f) g (.) . (.) f g = ((.) f) . g (.) . (.) f g a = ((.) f) (g a) (.) . (.) f g a = (.) f (g a) (.) . (.) f g a = f . (g a) (.) . (.) f g a b = f . (g a) $ b (.) . (.) f g a b = f ((g a) b) (.) . (.) f g a b = f (g a b) Cheers Christophe Brian Hulley wrote: Brian Hulley wrote: Taral wrote: On 5/28/06, Dominic Steinitz <[EMAIL PROTECTED]> wrote: Is this defined in some library? Thanks, Dominic. Don't think so. I use: \a b -> f (g a b) I don't see how (.) . (.) translates into something so simple. Using c for (.) to make things easier to write, I get: (.) . (.) === c c c === \x -> (c c c x) === \x -> (c (c x)) === \x -> (\y z -> c (c x) y z) Here was one error so fixing it and continuing: \x -> (c (c x)) === \x -> (\y z -> c (c x) z y) === \x -> (\y z -> (c x) (z y)) === \x -> (\y z -> (\p q -> c x q p) (z y)) === \x -> (\y z -> (\p q -> x (q p)) (z y)) === \x -> (\y z -> (\q -> x (q (z y === \x y z q -> x (q (z y)) But it still doesn't match f (g a b)... Regards, Brian. ___ Haskell mailing list Haskell@haskell.org http://www.haskell.org/mailman/listinfo/haskell -- Christophe Poucet Ph.D. Student Phone:+32 16 28 87 20 E-mail: Christophe (dot) Poucet (at) imec (dot) be Website: http://notvincenz.com/ IMEC vzw – Register of Legal Entities Leuven VAT BE 0425.260.668 – Kapeldreef 75, B-3001 Leuven, Belgium – www.imec.be *DISCLAIMER* This e-mail and/or its attachments may contain confidential information. It is intended solely for the intended addressee(s). Any use of the information contained herein by other persons is prohibited. IMEC vzw does not accept any liability for the contents of this e-mail and/or its attachments. ** ___ Haskell mailing list Haskell@haskell.org http://www.haskell.org/mailman/listinfo/haskell
[Haskell] TypeCasting in Haskell
Dear all,
I typically use indirect composite for making AST's. It allows me to
easily make new types with other annotations without having to duplicate
all elements but only those that actually change. It also allows a whole
amalgam of other possibilities. Recently I have observed a type error
which seems to be fixable only by doing a "typecast". What do I call a
typecast, you may ask? Basically a noop that changes the type. Here
attached you will find the code that demonstrates this.
module TypeCast where
data FooBar foo bar = --- Indirect composite
Foo { unFoo :: foo}
| Bar { unBar :: bar}
--- Assume some PFoobar (parsed)
data PFooBar = PF {unPF :: FooBar String String}
--- Assume some TFoobar (typed)
data TFooBar = TF {unTF :: FooBar Int String }
-- Merrily we write our conversion, using binding to optimize slightly
typer :: PFooBar -> TFooBar
typer pFooBar =
case unPF pFooBar of
[EMAIL PROTECTED] { unFoo = foo} -> -- We only need to change foo
TF $ f{unFoo = 1}
[EMAIL PROTECTED] { unBar = bar} -> -- We don't need to change this string
TF $ b -- So we just return b
--- Nice little main to make this a full module:
main :: IO ()
main = do
print . typer . PF . Foo $ "Hello"
--- Type error:
-- TypeCast.hs:19:11:
-- Couldn't match `Int' against `String'
-- Expected type: FooBar Int String
-- Inferred type: FooBar String String
-- In the second argument of `($)', namely `b'
-- In a case alternative: ([EMAIL PROTECTED] {unBar = bar}) -> TF $ b
--- what is the fix? Basically do a noop on b
--- [EMAIL PROTECTED] {unBar = bar} ->
--- TF $ b{unBar = bar}
Cheers,
Christophe
--
Christophe Poucet
Ph.D. Student
Phone:+32 16 28 87 20
E-mail: Christophe (dot) Poucet (at) imec (dot) be
Website: http://notvincenz.com/
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*DISCLAIMER*
This e-mail and/or its attachments may contain confidential information. It is
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Any use of the information contained herein by other persons is prohibited.
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Re: [Haskell] GHC Hackathon
Dear all, I think the hackathon sounds like a very interesting idea, however unfortunately I will not be able to attend, and I have heard that other people from #haskell will not be able to attend either. I think many would be grateful if a podcast were made of this event such that those who missed it can still watch the presentations. With regards, Christophe (vincenz) Simon Peyton-Jones wrote: Friends, A couple of weeks ago Simon M advertised the possibility that he and I might run a "GHC Hackathon", in Portland, later this year prior to ICFP (Sept 14-16 or thereabouts). The idea is that we'd give an extended tutorial about GHC's glorious innards. Then we'd have some hacking time in which you can pick something which you think GHC could do better, and implement it, with Simon and me wandering causing trouble. (E.g. look at GHC's list of tasks http://hackage.haskell.org/trac/ghc/report/2, but don't limit yourself to those.) [snip] -- Christophe Poucet Ph.D. Student Phone:+32 16 28 87 20 E-mail: [EMAIL PROTECTED] IMEC vzw – Register of Legal Entities Leuven VAT BE 0425.260.668 – Kapeldreef 75, B-3001 Leuven, Belgium – www.imec.be *DISCLAIMER* This e-mail and/or its attachments may contain confidential information. It is intended solely for the intended addressee(s). Any use of the information contained herein by other persons is prohibited. IMEC vzw does not accept any liability for the contents of this e-mail and/or its attachments. ** ___ Haskell mailing list Haskell@haskell.org http://www.haskell.org/mailman/listinfo/haskell
