The portable parts of Control.Monad.State (that are sufficient for most
cases) should be in an extra module (maybe called Control.Monad.StateTypes).
In addition further non-overloaded names for put, get, gets and modify would
be needed (maybe putState, getState, etc.)
I fear, this would complicate
At a casual glance, your Labeller looks to me like a state transformer monad.
I've found that the State transformer monad in the hierarchical libraries
can be useful for this kind of thing; the following example is part of a
larger program, so it can't be run in isolation, but I hope it shows so
On Thursday, 2003-06-26, 23:57, CEST, Derek Elkins wrote:
> [...]
> > not deeply understanding the use of Haskell extensions in the State
> > source,
>
> I'm assuming Control.Monad.State's source in which case -no- extensions are
> used for -State- (well, at least I don't see any quickly glancing)
On Friday, 2003-06-27, 12:55, CEST, Christian Maeder wrote:
> [...]
> The portable parts of Control.Monad.State (that are sufficient for most
> cases) should be in an extra module (maybe called Control.Monad.StateTypes).
> In addition further non-overloaded names for put, get, gets and modify woul
The previous "newtype Labeller a = Labeller (Int -> (Int, a))" (the
result tuple is reversed within Control.Monad.State) would simply become
(untested):
newtype Labeller a = State Int a
newLabel = do { n <- get; put (n + 1); return (Label n) }
runLabeller l = execState l minBound
it must be "e
not deeply
understanding the use of Haskell extensions in the State source,
I'm assuming Control.Monad.State's source in which case -no- extensions
are used for -State- (well, at least I don't see any quickly glancing).
Extensions are used for the -MonadState class-.
The portable parts of Con
On Thu, 26 Jun 2003 14:40:51 -0400 (EDT)
Mark Carroll <[EMAIL PROTECTED]> wrote:
> Not really seeing why Unique is in the IO monad,
What Unique? The one in the GHC source? If so, it seems that it's so
you can create multiple unique supplies that don't overlap. Since the
unique supply isn't a m
> (a) People could point out to me where I'm still confused, as
> revealed by
> my code. Is it needlessly complicated?
looks pretty reasonable to me :)
as to why Unique is in the IO monad is probabyl because if it were in
any other monad, you could start the monad twice and thus get a repeat
of
Not really seeing why Unique is in the IO monad, not deeply understanding
the use of Haskell extensions in the State source, and wanting to try to
learn a bit more about monads, I thought I'd try to write my own monad for
the first time: something for producing a series of unique labels. This is
ho
