Ganesh Sittampalam wrote:
In any case, what I'm trying to establish below is that it should be a
safety property of - that the entire module (or perhaps mutually
recursive groups of them?) can be duplicated safely - with a new name,
or as if with a new name - and references to it randomly
Ashley Yakeley wrote:
Ganesh Sittampalam wrote:
In any case, what I'm trying to establish below is that it should be
a
safety property of - that the entire module (or perhaps mutually
recursive groups of them?) can be duplicated safely - with a new
name,
or as if with a new name - and
David Menendez wrote:
Isn't that what we have right now? Typeable gives you a TypeRep, which
can be compared for equality. All the introspection stuff is in Data.
Oh, yes, you're right.
--
Ashley Yakeley
___
Haskell-Cafe mailing list
On Wed, Sep 3, 2008 at 2:53 AM, Ashley Yakeley [EMAIL PROTECTED] wrote:
It's worth mentioning that the current Data.Unique is part of the standard
base library, while hs-plugins is rather experimental. Currently Data.Unique
uses the NOINLINE unsafePerformIO hack to create its MVar. If
Dave Menendez wrote:
The Haskell 98 report includes NOINLINE, but
also states that environments are not required
to respect it. So hs-plugins wouldn't necessarily
be at fault if it didn't support Data.Unique.
Also, the definition of NOINLINE in the report doesn't
preclude copying both the
Sittampalam, Ganesh wrote:
That's not acceptable. This would cause Unique to break,
as its MVar would be created twice. It would also mean
that individual Unique and IOWitness values created by
- would have different values depending on which bit
of code was referencing them. It would render
David Menendez wrote:
On Wed, Sep 3, 2008 at 2:53 AM, Ashley Yakeley [EMAIL PROTECTED] wrote:
It's worth mentioning that the current Data.Unique is part of the standard
base library, while hs-plugins is rather experimental. Currently Data.Unique
uses the NOINLINE unsafePerformIO hack to create
Ashley Yakeley wrote:
I don't understand. If the dynamic loader were to load the same
package
name and version, and it duplicated the MVar, then Unique values would
have the same type and could be compared.
I am suggesting that this duplication process, whether conducted by the
dynamic loader
Ashley Yakeley wrote:
To solve this the hs-plugins dynamic loader maintains
state storing a list of what modules and packages have
been loaded already. If load is called on a module that
is already loaded, or dependencies are attempted to load,
that have already been loaded, the dynamic
Sittampalam, Ganesh wrote:
I am suggesting that this duplication process, whether conducted by the
dynamic loader or something else, should behave as if they did not have
the same package name or version.
This is certainly a valid transformation for Data.Unique, I am simply
saying that it
Henry Laxen wrote:
Have I, like Monsier Jourdain, been running in the IO monad all my
life, and didn't even know it?
Marc Weber wrote:
Sure...
But the ghci error message is another one:
Try this:
:set -XNoMonomorphismRestriction
And I highly recommend putting that line in your .ghci file.
Ashley Yakeley wrote:
Sittampalam, Ganesh wrote:
I am suggesting that this duplication process, whether conducted by
the dynamic loader or something else, should behave as if they did
not
have the same package name or version.
This is certainly a valid transformation for Data.Unique,
Ramin wrote:
...no matter how many tutorials I read, I find the only
kind of monad I can write is the monad that I copied
and pasted from the tutorial...
I am writing a mini-database...
The query itself is stateful...
The query may also make updates to the records.
I also
thought of trying
Sittampalam, Ganesh wrote:
I think it treats them as compatible, using the fact that
Data.Typeable returns the same type reps (which was why I initially
mentioned Data.Typeable in this thread). This is fine for normal
modules. There's a bit of description in the Dynamic Typing section of
Ashley Yakeley wrote:
I think it's bad design for a dynamic loader to load a module more
than once anyway.
In compiled code module boundaries don't necessarily exist. So how
do you relink the loaded code so that it points to the unique copy
of the module?
It's a waste of memory, for a
Hi,
I'd like to write a data structure to be used inside the IO monad.
The structure has some handles of type Maybe (IORef a),
i.e. IORef are pointers and the Maybe is like null pointers.
So I came up with the following functions :
readHandle :: Maybe (IORef a) - IO (Maybe a)
readField :: (a -
Ashley Yakeley wrote:
Currently Data.Unique uses the NOINLINE unsafePerformIO
hack to create its MVar. If hs-plugins duplicates that MVar,
that's a bug in hs-plugins.
Sittampalam, Ganesh wrote:
Also, the definition of NOINLINE in the report doesn't
preclude copying both the MVar *and* its
Yitzhak Gale wrote:
Right. It would not be a bug in hs-plugins. That is
the most urgent problem right now.
[...]
For the short term - can we *please* get an ONLYONCE
pragma that has the correct semantics?
So the purpose of this pragma would solely be so that
you can declare hs-plugins buggy
Hello minh,
Wednesday, September 3, 2008, 2:09:38 PM, you wrote:
I'd like to write a data structure to be used inside the IO monad.
The structure has some handles of type Maybe (IORef a),
i.e. IORef are pointers and the Maybe is like null pointers.
i've not used this but overall it seems
I really learned a lot from writing the below code,
and thought I'd share it with the group. I'm slightly
at a loss for words, having just spent the last two
hours on this when I most certainly should have
been doing other work, but these are two hours
I won't regret. I'm very interested in
Looks like MaybeT?
http://hackage.haskell.org/cgi-bin/hackage-scripts/package/MaybeT-0.1.1
readHandle x = runMaybeT $ do
ref - MaybeT (return x)
liftIO (readIORef ref)
readField f h = runMaybeT $ do
a - MaybeT (readHandle h)
return (f a)
(or, the short version)
readHandle
I wrote:
For the short term - can we *please* get an ONLYONCE
pragma that has the correct semantics?
Sittampalam, Ganesh wrote:
So the purpose of this pragma would solely be so that
you can declare hs-plugins buggy for not respecting it?
No, the hs-plugins problem - whether hypothetical or
(apologies for misspelling your name when quoting you last time)
Yitzchak Gale wrote:
For the short term - can we *please* get an ONLYONCE pragma that has
the correct semantics?
Until a permanent solution is implemented and deployed in the
compilers (if ever), can we please have a pragma
2008/9/3 Bulat Ziganshin [EMAIL PROTECTED]:
Hello minh,
Wednesday, September 3, 2008, 2:09:38 PM, you wrote:
I'd like to write a data structure to be used inside the IO monad.
The structure has some handles of type Maybe (IORef a),
i.e. IORef are pointers and the Maybe is like null
For the short term - can we *please* get an ONLYONCE pragma that has
the correct semantics?
Sittampalam, Ganesh wrote:
How do you propose that this pragma would be implemented?
As far as I know now, in GHC it could currently just be
an alias for NOINLINE, but the GHC gurus could say for sure.
Yitzchak Gale wrote
Other applications and libraries that support the pragma - such as
other
compilers, and hs-plugins - would be required to respect the
guarantee, and bugs could be filed against them if they don't.
If hs-plugins were loading object code, how would it even know of the
I wrote
Other applications and libraries that support the pragma -
such as other compilers, and hs-plugins - would be
required to respect the guarantee, and bugs could be
filed against them if they don't.
Sittampalam, Ganesh wrote:
If hs-plugins were loading object code, how would it even
2008/9/3 Lennart Augustsson [EMAIL PROTECTED]:
I think you should think about why your application needs IORef at all. Do
you really need mutation? And why isn't STRef good enough. Using IORef is
really the last resort.
This is for an interactive application (3D mesh editing, the data
Jason Dusek wrote:
Is anyone on the list using GHC on Joyent's Solaris (x86_64)
setup? If so, I would love to know whether it was easy/hard
and what the process is.
Sorry, I don't know a thing about Joyent. On x86-Solaris there seems
to exist only a 32bit distribution that should run on
On Wed, Sep 3, 2008 at 9:30 AM, Yitzchak Gale [EMAIL PROTECTED] wrote:
I wrote
Other applications and libraries that support the pragma -
such as other compilers, and hs-plugins - would be
required to respect the guarantee, and bugs could be
filed against them if they don't.
Sittampalam,
Brandon S. Allbery KF8NH wrote:
You can define a set of valid transformations, have the interpreter
log each transformation, and verify that all are correct (that is,
that both the transformation and the logged result are correct.
This assumes the interpreter can be resolved down to a
Brandon S. Allbery KF8NH wrote:
On 2008 Sep 1, at 14:47, Andrew Coppin wrote:
I wonder - how do the GHC developers check that GHC works properly?
(I guess by compiling stuff and running it... It's a bit harder to
check that a lambda interpretter is working right.)
GHC has a comprehensive
On Wednesday 03 September 2008 12:09:38 minh thu wrote:
Hi,
I'd like to write a data structure to be used inside the IO monad.
The structure has some handles of type Maybe (IORef a),
i.e. IORef are pointers and the Maybe is like null pointers.
So I came up with the following functions :
Sittampalam, Ganesh wrote:
In compiled code module boundaries don't necessarily exist. So how
do you relink the loaded code so that it points to the unique copy
of the module?
hs-plugins loads modules as single .o files, I believe.
It crashes the RTS of the plugins loader, which is based on
It would be great if there were an automated or semi-automated way
of generating a MacPorts Portfile from a HackageDB package, along
the lines of dons' cabal2arch. Has anyone been working on such a thing?
And, are any haskell-cafe readers MacPorts committers?
John
I am currently involved with a Haskell project to create a toolset for a
formal language. The toolset contains a parser, a typechecker and s range of
other features.
The Haskell code currently consists of about 20 modules. I am new in the
project, and my impression is that a lot of code does not
On Wed, 2008-09-03 at 13:14 -0700, John MacFarlane wrote:
It would be great if there were an automated or semi-automated way
of generating a MacPorts Portfile from a HackageDB package, along
the lines of dons' cabal2arch. Has anyone been working on such a thing?
And, are any haskell-cafe
j.m.m.joosten:
I am currently involved with a Haskell project to create a toolset for a
formal language. The toolset contains a parser, a typechecker and s range of
other features.
The Haskell code currently consists of about 20 modules. I am new in
the project, and my impression is that
duncan.coutts:
On Wed, 2008-09-03 at 13:14 -0700, John MacFarlane wrote:
It would be great if there were an automated or semi-automated way
of generating a MacPorts Portfile from a HackageDB package, along
the lines of dons' cabal2arch. Has anyone been working on such a thing?
And, are
On 2008.08.24 11:41:04 -0400, Eric Kidd [EMAIL PROTECTED] scribbled 3.7K
characters:
Greetings, Haskell folks!
I'm working on a toy program for drum synthesis. This has lead me to
explore the various sound-related libraries in Hackage. Along the way,
I've learned several things:
1.
On Wed, Sep 3, 2008 at 4:14 PM, John MacFarlane [EMAIL PROTECTED] wrote:
It would be great if there were an automated or semi-automated way
of generating a MacPorts Portfile from a HackageDB package, along
the lines of dons' cabal2arch. Has anyone been working on such a thing?
And, are any
On Wed, Sep 3, 2008 at 11:34 AM, Andrew Coppin
[EMAIL PROTECTED] wrote:
data Expression = Var String | Apply Expression Expression | Lambda String
Expression
How would you go about building random expression trees?
It's pretty simple, I think. Keep an environment of variable names
that are
On 2008 Sep 3, at 14:34, Andrew Coppin wrote:
Brandon S. Allbery KF8NH wrote:
You can define a set of valid transformations, have the interpreter
log each transformation, and verify that all are correct (that is,
that both the transformation and the logged result are correct.
This assumes
Jonathan Cast wrote:
But Haskell's community is also growing
This is good!
and becoming more
results-oriented.
This is not; see my other post. I think it's great that Haskellers are
starting to accomplish useful things, but if in the process I think
elders like Lennart Augustsson and
Ramin wrote:
Hello, I'm new here, but in the short time I have known Haskell, I can
already say it's my favorite computer language.
Except for monads, and no matter how many tutorials I read, I find the
only kind of monad I can write is the monad that I copied and pasted
from the tutorial,
Dear Haskellers,
Some time ago the question was asked on gtk2hs mailing list about how to
work with *.po files, i.e. how to make Haskell program i18n-aware. (see
http://thread.gmane.org/gmane.comp.lang.haskell.gtk2hs/592)
The answer was that Gtk2hs does not have gettext support
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