I've read 4 messages following this, but I'd like to pursue this a little
to test my own understanding...
At 14:12 30/12/03 +, Joe Thornber wrote:
I was wondering if anyone could give me some help with this problem ?
I'm trying to hold some state in a StateMonad whilst I iterate over a
On Wed, Dec 31, 2003 at 11:54:27AM +, Graham Klyne wrote:
My *intuition* here is that the problem is with countLeaves2, in that it
must build the computation for the given [sub]tree before it can start to
evaluate it. Maybe this is why other responses talk about changing the
state
At 12:36 31/12/03 +, Joe Thornber wrote:
On Wed, Dec 31, 2003 at 11:54:27AM +, Graham Klyne wrote:
My *intuition* here is that the problem is with countLeaves2, in that it
must build the computation for the given [sub]tree before it can start to
evaluate it. Maybe this is why other
On Wed, Dec 31, 2003 at 02:38:06PM +, Graham Klyne wrote:
getOrCachePositionValue pos =
do { mcache - gets (findPos pos) -- Query cache for position
; case mcache of
Just cached - return (cachedVal cached) -- Return cached value
Nothing -
Hi,
Can anyone explain to me how hugs manages to derive that
f x y z = y (y z) x
is of type
f :: a - ((a - b) - a - b) - (a - b) - b
Many thanks and a happy new year to all!
Lee
_
Stay in touch with absent friends - get MSN
On 2003-12-31 at 19:27GMT Lee Dixon wrote:
Hi,
Can anyone explain to me how hugs manages to derive that
f x y z = y (y z) x
is of type
f :: a - ((a - b) - a - b) - (a - b) - b
To begin with, f has three arguments, x y and z, so letting
each of these have types Tx Ty and Tz, f has to
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 way to
translate from the first's state to the second to keep the chain
going.
I can easily write something for
I tried posting this before but, from my point of view, it vanished. My
apologies if it's a duplicate.
In http://www.cs.uu.nl/~daan/download/parsec/parsec.html we read,
testOr2 = try (string (a))
| string (b)
or an even better version:
testOr3 = do{ try (string (a); char ')';
Mark,
I'm no expert, but does it help to start from withStateT?
withStateT :: (s - s) - StateT s m a - StateT s m a
withStateT f m = StateT $ runStateT m . f
There are some notes about computations and lifting
state transformers in
Modular Denotational Semantics for Compiler Construction
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 way to
On Wed, 31 Dec 2003, Ken Shan wrote:
Don't you need a (s2 - s1) function as well, to translate the final
state back into StateT s1?
Yes, you're right: the thing actually running the stateful computation
presumably expects to start it with a state of type s1 and to be able to
extract from it a
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