Mark Carroll <[EMAIL PROTECTED]> wrote in article <[EMAIL PROTECTED]> in
gmane.comp.lang.haskell.cafe:
> Omitting the typeclass bit, I'm trying to write something like
> (s1 -> s2) -> StateT s1 m () -> StateT s2 m a -> StateT s1 m a
>
> That is, it sequences two StateT computations, providing a w
On 2003-12-08T12:42:46-0800, Jeffrey A. Scofield wrote:
> b = () -> (a, b)
> [...]
> I'm wondering how to tell, as a relative newcomer to
> Haskell, that they aren't allowed.
I think the rule you're looking for is the following: Don't equate a
type variable with something that contains that ty
On 2003-11-13T13:19:28-, Simon Peyton-Jones wrote:
> | From: [EMAIL PROTECTED]
> |
> | Has anyone thought about adding hereditary Harrop formulas, in other
> | words hypothetical reasoning and universal quantification, to the
> | instance contexts in the Hsakell type class system?
>
> Yes, ab
d "(*->*)->?" (aka constructor classes), but also types of kind
"(*->?)->(*->?)". But that's for another day...
Ken
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"Hi, my name is Kent, and I let people change my .sig on
Brandon Michael Moore <[EMAIL PROTECTED]> wrote in article <[EMAIL PROTECTED]> in
gmane.comp.lang.haskell.cafe:
> There are two extensions here:
>
> More overlapping: [...]
> Backtracking search: [...]
>
> Overloading resolution: [...]
I'm sorry if I am getting ahead of Simon or behind of you,
Peter Pudney <[EMAIL PROTECTED]> wrote in article <[EMAIL PROTECTED]> in
gmane.comp.lang.haskell.cafe:
> Did I dream this, or was it
> a feature of Miranda*, Gopher or Hugs many years ago?
I just wanted to see that asterisk again.
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On 2003-02-21T13:37:26-0500, Mike T. Machenry wrote:
> Eh, state is not possible. This is a recursive state space search. I need
> to branch the state of the game and not allow branches to effect others.
I see-- so you don't care about performing array updates in place,
because you will be copying
On 2003-01-08T09:19:10+0200, Max Ischenko wrote:
> - To be able to run it both in Hugs and by GHC I need an
>`import Data.Char(isSpace) for GHC`. Can this be conditionally
>included in a source for GHC only?
You could use say the C preprocessor to do this, but a better way to
solve your p
On 2002-09-21T12:56:13-0700, Russell O'Connor wrote:
> case (number g) of
> Just n -> Just (show n)
> Nothing ->
> case (fraction g) of
>Just n -> Just (show n)
>Nothing ->
> case (nimber g) of
> Just n -> Just ("*"++(show n))
> Nothing -> Nothing
How about something lik
On 2002-08-08T14:11:54-0500, Shawn P. Garbett wrote:
> newtype St a s = MkSt (s -> (a, s))
> instance Monad St where
This line should say
instance Monad (St a) where
because it is (St a) that is a Monad, not St by itself.
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Hello,
In Haskell, backquotes can be used to convert individual identifiers
into infix operators, but not complex expressions. For example,
[1,2,3] `zip` [4,5,6]
is OK, but not
[1,2,3] `zipWith (+)` [4,5,6]
Is there any reason other than potential confusion when one of the two
backqu
A while ago, to help myself understand newtype, data, and strictness,
I tried to write down how Haskell types correspond to lifted domains.
Here is a cleaned-up version of my attempt. I am not sure that what
follows is entirely correct -- please point out any errors. I would
also appreciate comm
On 2001-07-25T14:39:06-0400, Mark Carroll wrote:
> Do any of the decent Haskell compilers allow you to just type function
> definitions at an interpreter prompt and use them in subsequent
> interactions, as you'd expect from a Lisp environment? I'm fed up of
> editing a tiny file separately and ty
On 2001-06-01T17:59:25+0100, Ross Paterson wrote:
> Here's a negative space hack that gives extensible brackets: write
> \Sem{expr} to wrap an expression. (Doubtless someone who knows TeX
> could do better.)
Ah! Neat. [One wishes that TeX could consider arbitrary code to be
delimiter definitio
On 2001-06-01T08:41:34-0700, Andrew Moran wrote:
> There's also \llbracket and \rrbracket, from stmaryrd. They look better than
> the negative space hack, IMHO (now all I need is for Alan Jeffrey to write in
> and say that \{ll,rr}bracket are implemented with the negative space hack :-)
Heh. Ac
On 2001-05-27T22:46:37-0500, Jay Cox wrote:
> >data S m a = Nil | Cons a (m (S m a))
>
> >instance (Show a, Show (m (S m a))) => Show (S m a) where
> > show Nil = "Nil"
> > show (Cons x y) = "Cons " ++ show x ++ " " ++ show y
Here's how I've been handling such situations:
data S m a = Ni
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