Simon Peyton-Jones [EMAIL PROTECTED] writes:
The Haskell committee [...]
there *is* no Haskell committee!
Fnord!
* You can offer it for inclusion in hslibs/, an evolving
collection of libraries that are distributed with
GHC and Hugs
Perhaps we could organize a network
Kuncak wrote:
| Why don't we have "deriving Functor" in Haskell?
Tom Pledger answered:
| I don't know how significant this is, but types
| declared as Functor instances have kind (*-*),
| whereas types with any derived instances have kind *.
This might be the historical reason why Functor
| The (or at least, my) hope is that there will be an
| extension to Haskell soon (called "Generic Haskell") which
| will make this easy to do.
Indeed, Ralf Hinze and I are working on a Haskell workshop
paper on this very topic, and I hope that a summer intern,
Andrei Serjantov, will be able to
Is anyone else working on Generic Haskell.
Yes, I have an MSc student (Jan de Wit) who will work on Generic Haskell,
and I expect more people will start working on it in Utrecht later this year.
Johan
Marcin 'Qrczak' Kowalczyk wrote:
Haskell's type system is powerful, but cannot express anything at
compile time. Very dynamic domains must be represented as runtime
objects, i.e. values. These values and elements of those domains have
carefully designed types, because Haskell is statically
Rob MacAulay quoting M. Kowalczyk:
Classes are not the appropriate tool for modelling domains of a
sufficiently advanced algebra system.
If I understand correctly, you propose a system where Domains are
record types, whose fields are functions corresponding to
operations in the Domain.
Hi,
I am trying to reproduce the fuzzy oscillator example by Jan Skibinski.
( http://www.numeric-quest.com/haskell/Fuzzy_oscillator.html )
I am having problems to compile the module Fuzzy.hs. As I am
just in an early learning stage, I need help to understand the error.
hugs98 e.g. says:
On Fri, 12 May 2000, Wilhelm B. Kloke wrote:
Hi,
I am trying to reproduce the fuzzy oscillator example by Jan Skibinski.
( http://www.numeric-quest.com/haskell/Fuzzy_oscillator.html )
I am having problems to compile the module Fuzzy.hs. As I am
just in an early learning stage, I need
Claus Reinke writes:
[nice exposition of C-H correspondence state threads]
The main caveat is the insistence on constructive proofs (in the classical
logic most of us tend to learn, there is this favourite proof technique: if
I assume that xs don't exist, I am led to a contradiction, so xs
nhc98 and ghc4.06 show a different message:
Fuzzy.hs:188: Variable not in scope: `fromInt'
The function "fromInt" is not part of Haskell'98. Replace its sole use
with "fromIntegral", and the module compiles just fine with nhc98.
Regards,
Malcolm
The Department of Computing and Electrical Engineering at
Heriot-Watt University, in Edinburgh, Scotland has a number
of EPSRC PhD Studentships available for UK and EU nationals
to undertake research in Functional Programming. The
department has a very active group working on parallel
Hi all,
Why is it that type synonyms can't be made class instances?
I suspect there's a good reason, but I can't figure it out.
The reason I ask is that I'm finding that definitions for monads are
obfuscated by the need for constructors and field accessors, whereas if
type synonyms could be
Fri, 12 May 2000 00:42:52 +0200, Jan Brosius [EMAIL PROTECTED] pisze:
newSTRef :: a - ST s (STRef s a)
readSTRef :: STRef s a - ST s a
and
f:: STRef s a - STRef s a
f v = runST( newSTRef v = \w - readSTRef w)
Let's start
v has type STRef s a
...for "s" and "a" coming from the
On Fri, 12 May 2000, Malcolm Wallace wrote:
nhc98 and ghc4.06 show a different message:
Fuzzy.hs:188: Variable not in scope: `fromInt'
The function "fromInt" is not part of Haskell'98. Replace its sole use
with "fromIntegral", and the module compiles just fine with nhc98.
Fri, 12 May 2000 11:47:11 -0600 (MDT), Thomas Harke [EMAIL PROTECTED] pisze:
Why is it that type synonyms can't be made class instances?
It does not add any functionality (see below), and could be confusing
because it would really make the instance for the expansion of the
type synonym (with
Thanks Marcin,
Marcin 'Qrczak' Kowalczyk wrote:
Thomas Harke [EMAIL PROTECTED] pisze:
Why is it that type synonyms can't be made class instances?
It does not add any functionality (see below), and could be confusing
because it would really make the instance for the expansion of the
Thomas Harke wrote:
Marcin 'Qrczak' Kowalczyk wrote:
[...] GHC developers decided that it is more convenient than
confusing and permitted to spell type synonyms in instance
definitions. I agree with it.
Now I'm confused. Do you mean I *can* do this in GHC? But the
Haskell Report
Thu, 11 May 2000 06:39:10 -0700, Simon Marlow
[EMAIL PROTECTED] pisze:
The solution, if you're interested, is to open the file in blocking
mode and set O_NONBLOCK later on with an fcntl().
It means that waiting for the writer blocks the whole program, right?
Yes, and that's another
On Fri, May 12, 2000 at 02:51:21AM -0700, Simon Marlow wrote:
I think the only recommendation is "don't use FIFOs" - I'm considering
backing out the fix now. A Unix domain socket provides the same facilities
and has reasonable semantics.
...though it isn´t the same as a FIFO as you you can´t
It is certainly better after a fix, at least for
single-threaded programs
which work perfectly.
With native threads (BTW, are they expected to work soon?) it
would work
well too.
Perhaps... but pthreads emulated in user-space would suffer from the same
problems as GHC, because they
Testing under Linux showed that after opening a fifo with O_NONBLOCK
we should call select on it before read: it will not say we can read
from it until another process opens it for writing.
And when another process opens it for writing and closes without
writing anything, select says we should
21 matches
Mail list logo
