* S D Swierstra doai...@uu.nl [2012-01-20 16:32:00+0100]
Thus far i have only happy users, and if you are having any problems
please let me know.
Hi Doaitse,
One thing that I'm curious about is how you avoid combinatorial
explosion when parsing in a breadth-first fashion. Do you somehow manage
Regions is an automatic resource management technique that statically
ensures that all allocated resources are freed and a freed resource
cannot be used. Regions also promote efficiency by helping to structure
the computation so that resources will be freed soon, and en
masse. Therefore, regions
Hello all
I have installed ghc-7.4.0.20111219 and this
announcementhttp://www.haskell.org/pipermail/glasgow-haskell-users/2011-December/021310.htmlsays
that The
release candidate accidentally includes the random, primitive, vector and
dph libraries. The final release will not include them. I
There is now a new GLFW package on hackage with version number
0.5.0.0. Maintainers of packages that depend on GLFW may want to
update your packages since (1) GLFW-0.4.2 is mostly broken on OS X
Lion (10.7); (2) there are incompatible API changes.
Notable changes include (but not limited to):
1.
On 2012-01-20 23:44, Gwern Branwen wrote:
On Fri, Jan 20, 2012 at 1:57 PM, Twan van Laarhoventwa...@gmail.com wrote:
Here is some example code (untested):
Well, you're right that it doesn't work. I tried to fix the crucial
function, 'atLeastThisManyDescendants', but it's missing something
On 01/18/2012 10:43 PM, Edward Z. Yang wrote:
Excerpts from Mikhail Vorozhtsov's message of Wed Jan 18 08:47:37 -0500 2012:
Well, that's the kind of language we live in. The denotation of our language
always permits for bottom values, and it's not a terribly far jump from there
to undefined
On 20/01/2012 03:23, Edward Z. Yang wrote:
Oh, I'm sorry! On a closer reading of your message, you're asking not
only asking why 'fail' was added to Monad, but why unfailable patterns
were removed.
Well, from the message linked:
In Haskell 1.4 g would not be in MonadZero because (a,b)
Hi Myles,
These sound like two solid features, and I'd be happy to merge in code to
support it. Some comments below.
On Sat, Jan 21, 2012 at 8:38 AM, Myles C. Maxfield myles.maxfi...@gmail.com
wrote:
To: Michael Snoyman, author and maintainer of http-conduit
CC: haskell-cafe
Hello!
I am
On Sat, Jan 21, 2012 at 06:47, mukesh tiwari
mukeshtiwari.ii...@gmail.comwrote:
I have installed ghc-7.4.0.20111219 and this
announcementhttp://www.haskell.org/pipermail/glasgow-haskell-users/2011-December/021310.htmlsays
that The
release candidate accidentally includes the random,
The do notation translates
do {x - a;f} into
a=(\x - f)
However when we're working in the IO monad the semantics we want requires that
the lambda expression be strict in its argument. So is this a special case for
IO? If I wanted this behavior in other monads is there a way to specify
Hi Brandon
Thank you for reply. Could you please tell me how to install dph
because cabal install is not working with ghc-7.4.0.20111219 and I
have issue with ghc-7.2.1 and dph
Macintosh-0026bb610428:src mukesh$ ghci -Odph -fdph-par
on the commandline:
Warning: -O conflicts with
On 21 Jan 2012, at 21:29, Victor S. Miller wrote:
The do notation translates
do {x - a;f} into
a=(\x - f)
However when we're working in the IO monad the semantics we want requires
that the lambda expression be strict in its argument. So is this a special
case for IO? If I wanted
* Victor S. Miller victorsmil...@gmail.com [2012-01-21 12:29:32-0500]
The do notation translates
do {x - a;f} into
a=(\x - f)
However when we're working in the IO monad the semantics we want
requires that the lambda expression be strict in its argument.
I'm not aware of any semantics
On Sat, Jan 21, 2012 at 12:50, mukesh tiwari
mukeshtiwari.ii...@gmail.comwrote:
Hi Brandon
Thank you for reply. Could you please tell me how to install dph
because cabal install is not working with ghc-7.4.0.20111219 and I
have issue with ghc-7.2.1 and dph
Sorry, but I don't know. I don't
As noted, IO is not strict in the value x, only in the operation that
generates x. However, should you desire strictness in a generic way, it
would be trivial to model a transformer monad to provide it.
E.g.
data StrictT m a = StrictT (m a)
runStrictT :: StrictT m a - m a
runStrictT (StrictT
On 21/01/2012 17:29, Victor S. Miller wrote:
The do notation translates
do {x- a;f} into
a=(\x - f)
However when we're working in the IO monad the semantics we want requires that
the lambda expression be strict in its argument. So is this a special case for
IO? If I wanted this behavior
* David Barbour dmbarb...@gmail.com [2012-01-21 10:01:00-0800]
As noted, IO is not strict in the value x, only in the operation that
generates x. However, should you desire strictness in a generic way, it
would be trivial to model a transformer monad to provide it.
Again, that wouldn't be a
Hi Conal,
On Sun, Jan 15, 2012 at 6:45 AM, Conal Elliott co...@conal.net wrote:
I'm using haskell-src-exts together with SYB for a code-rewriting project,
and I'm having difficulty with parenthesization. I naïvely expected that
parentheses would be absent from the abstract syntax, being
On 21/01/2012 18:08, Steve Horne wrote:
Even so, to see that strictness isn't the issue, imagine that (=)
were rewritten using a unary executeActionAndExtractResult function.
You could easily rewrite your lamba to contain this expression in
place of x, without actually evaluating that
On Sat, Jan 21, 2012 at 10:08 AM, Roman Cheplyaka r...@ro-che.info wrote:
* David Barbour dmbarb...@gmail.com [2012-01-21 10:01:00-0800]
As noted, IO is not strict in the value x, only in the operation that
generates x. However, should you desire strictness in a generic way, it
would be
Neil Mitchell's HLint (http://community.haskell.org/~ndm/hlint/) warns
about extra parens in Haskell code. So, it must have code for
detecting those. I wonder if you can just insert parens liberally in a
first run, and then use his algorithm to remove those that are
unnecessary. The two passes can
On Sat, Jan 21, 2012 at 1:45 PM, David Barbour dmbarb...@gmail.com wrote:
On Sat, Jan 21, 2012 at 10:08 AM, Roman Cheplyaka r...@ro-che.info wrote:
* David Barbour dmbarb...@gmail.com [2012-01-21 10:01:00-0800]
As noted, IO is not strict in the value x, only in the operation that
generates
On Sat, Jan 21, 2012 at 10:51 AM, David Menendez d...@zednenem.com wrote:
The Eval monad has the property: return undefined = const e = e.
You can't write `const e` in the Eval monad.
From what I can tell, your proposed monads do not.
You can't write `const e` as my proposed monad,
* David Barbour dmbarb...@gmail.com [2012-01-21 11:02:40-0800]
On Sat, Jan 21, 2012 at 10:51 AM, David Menendez d...@zednenem.com wrote:
The Eval monad has the property: return undefined = const e = e.
You can't write `const e` in the Eval monad.
Why not?
ghci runEval $ return
Oops, I was misreading. You have `e` here as the next monad.
In any case, I think the monad identity concept messed up. The property:
return x = f = f x
Logically only has meaning when `=` applies to values in the domain.
`undefined` is not a value in the domain.
We can define monads - which
On Sat, Jan 21, 2012 at 11:08 AM, Roman Cheplyaka r...@ro-che.info wrote:
* David Barbour dmbarb...@gmail.com [2012-01-21 11:02:40-0800]
On Sat, Jan 21, 2012 at 10:51 AM, David Menendez d...@zednenem.com
wrote:
The Eval monad has the property: return undefined = const e = e.
You
* David Barbour dmbarb...@gmail.com [2012-01-21 11:09:43-0800]
Logically only has meaning when `=` applies to values in the domain.
`undefined` is not a value in the domain.
We can define monads - which meet monad laws - even in strict languages.
In strict languages 'undefined' is not a
Excerpts from Mikhail Vorozhtsov's message of Sat Jan 21 09:25:07 -0500 2012:
But I also believe that you can't use this as justification to stick your
head in the sand, and pretend bottoms don't exist (regardless of whether or
not we'rd talking about asynchronous exceptions.) The reason is
`undefined` is not a value in any domain. It isn't a value at all. It's
certainly not part of my monad language or algebra. Up to the semantic
level of comparing observable and legally defined behaviors, we can have
the identity law. That's sufficient for the letter of the law, even if not
ideal
I'm finding a rather unusual problem as I write haskell..
Unlike every other language I've used, large portions of my haskell code
are turning out to be general-purpose, reusable code. Fully 20% of the
haskell code I've written for git-annex is general purpose. Now, I came out
of a decade of perl
On 2012-01-21 16.20.25 -0400, Joey Hess wrote:
My problem now is that as I start new projects, I want to have my haskell
utility functions available, and copying them around is not ideal. So, put
them on hackage. But where, exactly?
Instead of putting all of them in one package, how about you
You might find many of these on hackage in various forms already.. it
might be easier to just depend on some of those libraries.
On Sat, Jan 21, 2012 at 04:20:25PM -0400, Joey Hess wrote:
Some quite generic monadic control functions, few of them truely unique:
whenM :: Monad m = m Bool -
The there is an amb combinator which you can use to lift an ambiguous parser
into one which returns a list of results. This will take care that the part
after the ambiguous non-terminal is only parsed once.
Like most libraries I do indeed not cache results of applying parsers at
specific
Bas van Dijk wrote:
What's the recommended way for serializing (with the cereal package) an
UTCTime?
Serialize the Day part as an Integer using
toModifiedJulianDay/ModifiedJulianDay,
(Note that Day is not a constructor, it's just the name of
the type.)
Serialize the DiffTime as a Rational, as
headMaybe :: [a] - Maybe a
Is this the same as Data.Maybe.maybeToList?
readMaybe :: Read a = String - Maybe a
This has been added to base recently [1].
Cheers,
Simon
[1]
https://github.com/ghc/packages-base/commit/0e1a02b96cfd03b8488e3ff4ce232466d6d5ca77
On Sat, Jan 21, 2012 at 4:32 AM, Paul Liu nine...@gmail.com wrote:
There is now a new GLFW package on hackage with version number
0.5.0.0.
Congrats!
[snip]
4. There is an outstanding bug preventing GLFW programs to be invoked
from GHCi on OS X. One has to compile before running GLFW
One thing I found useful when looking if a function already exists under a
different name is to use Hayoo to search for the type, i.e.:
http://holumbus.fh-wedel.de/hayoo/hayoo.html#0:(a%20-%3E%20Bool)%20-%3E%20%5Ba%5D%20-%3E%20(%5Ba%5D%2C%5Ba%5D)
- Chris
Thanks Ertugrul and Yitzchak. I failed to notice the Real and
Fractional instances for DiffTime. Thanks very much for pointing me to
it. I dropped the dependency on datetime and implemented your
suggestions.
Bas
On 21 January 2012 22:29, Yitzchak Gale g...@sefer.org wrote:
Bas van Dijk wrote:
There is also Hoogle, pretty equivalent I guess.
http://www.haskell.org/hoogle/
Thiago.
2012/1/21 Christoph Breitkopf chbreitk...@googlemail.com:
One thing I found useful when looking if a function already exists under a
different name is to use Hayoo to search for the type, i.e.:
On Sat, Jan 21, 2012 at 11:08 PM, Christoph Breitkopf
chbreitk...@googlemail.com wrote:
One thing I found useful when looking if a function already exists under a
different name is to use Hayoo to search for the type, i.e.:
Uh - please ignore the bogus link - I had blindly assumed that it
* David Barbour dmbarb...@gmail.com [2012-01-21 12:18:09-0800]
`undefined` is not a value in any domain. It isn't a value at all. It's
certainly not part of my monad language or algebra. Up to the semantic
level of comparing observable and legally defined behaviors, we can have
the identity
On Sat, Jan 21, 2012 at 2:24 PM, Roman Cheplyaka r...@ro-che.info wrote:
* David Barbour dmbarb...@gmail.com [2012-01-21 12:18:09-0800]
`undefined` is not a value in any domain. It isn't a value at all. It's
certainly not part of my monad language or algebra. Up to the semantic
level of
(StrictT op) = f = StrictT (op = \ x - x `seq` runStrictT (f x))
Are you sure? Here you evaluate the result, and not the computation itself.
Wouldn't it be:
(StrictT op) = f = op ` seq` StrictT (op = \x - runStrictT (f x))
??
2012/1/21 David Barbour dmbarb...@gmail.com
On Sat, Jan 21, 2012
Hello everyone,
So here is what I want to achieve:
I'd like a program that calculates the time needed for water to flow out of
a circuit made out of tube.
The rules are :
- There are multiple sources of water and only one exit.
- The water can only take one path from a source to the exit.
- Of
Evaluating the argument/result was my intention. Evaluating the computation
itself might be useful in some cases, though.
Regards,
Dave
On Sat, Jan 21, 2012 at 3:20 PM, Yves Parès yves.pa...@gmail.com wrote:
(StrictT op) = f = StrictT (op = \ x - x `seq` runStrictT (f x))
Are you sure?
On 2012-01-22 00:39, Pierre Penninckx wrote:
So here is what I want to achieve:
I'd like a program that calculates the time needed for water to flow out of a
circuit made out of tube.
The rules are :
- There are multiple sources of water and only one exit.
- The water can only take one path from
On Sat, Jan 21, 2012 at 2:05 PM, Jason Dagit dag...@gmail.com wrote:
4. There is an outstanding bug preventing GLFW programs to be invoked
from GHCi on OS X. One has to compile before running GLFW programs.
Does it still happen with -fno-ghci-sandbox? That fixes these sort of
bugs with
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