G'day all.
Quoting John Meacham [EMAIL PROTECTED]:
would it be possible to provide an Ord instance for (IORef a)?
It would, although then someone else would just want a hashable instance.
Sounds to me like it might be worth coming up with a general IORef (and
STRef) wrapper.
Until then, this
G'day all.
Quoting [EMAIL PROTECTED]:
Until then, this is what I use.
Second time lucky.
Cheers,
Andrew Bromage-
-- |
-- Module : Data.IOStableRef
-- Copyright : (c) Andrew Bromage 2002
-- License :
| From: John Meacham
| would it be possible to provide an Ord instance for (IORef a)? For
| things like loop detection, one may need to make many IORef
comparasions
| and being able to use an efficient set would be a really big win.
|
| Since IORefs are created in the IO monad, the actual order
If I have a polymorphic algebraic type (T a) with several type
data MyType a = A a | B String | C Int
So how do you expect to get the contents of B and C outm
when they are differenf Types - surely you mean:
data MyType a = A a | B MyStrings
Keean.
(I still think it's a bug though:-)
It is definitely not a bug... you cannot assert that the types:
Either String a
Either String b
are both equal ant not equal at the same time. You either mean:
f :: (a-a) - Either String a - Either String a
Or you mean
f :: (a-b) - Either String a - Either
On Tue, Jun 22, 2004 at 01:29:02PM +0100, MR K P SCHUPKE wrote:
data E a b
= L1 { r :: a }
| L2 { r :: a }
| L3 { r :: a }
| L4 { r :: a }
| R b
deriving Show
How is this different from:
data E a b = L1 a | L2 a | R b
f g (R a) = R (g a)
f _
On 22-Jun-2004, Simon Peyton-Jones [EMAIL PROTECTED] wrote:
My own view is that this is fine -- IORefs shouldn't be in your inner
loop, so an extra word in each is no big deal.
I find that attitude rather extraordinary and I do not agree.
For some applications, IORefs may well be a major
On Tue, Jun 22, 2004 at 02:52:21PM +0200, Tomasz Zielonka wrote:
Record update avoids this because of the way it is translated.
Basically, the result of record update is a reconstructed record, but
constructors not containing updated fields are not built/copied, so they
don't constrain the
Hi all,
I'm going to try to implement a version of Markdown tool[1] in Haskell.
The application is rather simple: take a text file with some (simple)
mark-up embedded in it and turn it into another text file, this time
with XHTML markup.
I need some guidelines on how to get started. I'll have
On Tuesday 22 Jun 2004 1:50 pm, MR K P SCHUPKE wrote:
(I still think it's a bug though:-)
It is definitely not a bug... you cannot assert that the types:
Either String a
Either String b
are both equal ant not equal at the same time.
I wasn't.
You either mean:
f :: (a-a) - Either
On Tue, 2004-06-22 at 20:52, Adrian Hey wrote:
On Tuesday 22 Jun 2004 6:20 pm, MR K P SCHUPKE wrote:
ahh but in this example:
f :: [Int] - [Bool]
f (i:is) = even i : f is
f [EMAIL PROTECTED] = e
e is an empty list of Ints not an empty list of Bools!
If the difference is
The GHC documentation on QSem is very sparse. I
would like to give a thread exclusive access to a
resource.
My *guess* based on the documentation is that I
can create an exclusive lock using:
logSem - newQSem 1
And then any thread that wants to lock the
resource uses:
withLogSem x = do
G'day all.
Quoting Fergus Henderson [EMAIL PROTECTED]:
I find that attitude rather extraordinary and I do not agree.
Me too. I've written more than one Haskell program where hash consing
is part of an inner loop. For this applciation the data structures
weren't that big, but I can easily
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