Bulat Ziganshin wrote:
examples of lifting C functions into Haskell world:
mysin :: Double - Double
mysin = realToFrac . c_mysin . realToFrac
-- c_mysin :: CDouble - CDouble
rnd :: Int - IO Int
rnd x = do r - c_rnd (fromIntegral x)
return (fromIntegral r)
-- c_rnd :: CInt - IO
Many architectures gives both the quotient and remainder when you use
the division instruction, so divMod (quotRem) shouldn't cost more
than a div or mod. But if the code generator takes advantage of that
is another matter.
On Feb 12, 2007, at 02:32 , Matthew Brecknell wrote:
I wrote:
Lennart Augustsson lennart at augustsson.net writes:
Yes, and that's pretty much what my version does (and what the
original tried to do?).
Yes, you're right, I see now that my method is equivalent to yours. (My
apologies, it was late.)
The point I was trying to make is that there are two
On Feb 12, 2007, at 5:45 AM, Matt Roberts wrote:
- The hackathon videos,
- A transformation-based optimiser for Haskell,
- An External Representation for the GHC Core Language (DRAFT for
GHC5.02), and
- Secrets of the Glasgow Haskell Compiler inliner.
Matt, can you please post
On Feb 12, 2007, at 7:06 AM, Stefan O'Rear wrote:
We have Core because Simon lacks the patience to solve the halting
problem and
properly perform effects analysis on STG.
We have STG because Simon lacks the patience to wait for the 6.6
Simplifier to
finish naively graph-reducing every
Chris Moline [EMAIL PROTECTED] writes:
dropWhile p = foldr (\x l' - if p x then l' else x:l') []
invalid: dropWhile ( 5) [1, 10, 1] should return [10, 1]
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pixel:
Chris Moline [EMAIL PROTECTED] writes:
dropWhile p = foldr (\x l' - if p x then l' else x:l') []
invalid: dropWhile ( 5) [1, 10, 1] should return [10, 1]
Prelude Test.QuickCheck Text.Show.Functions quickCheck $ \p xs - dropWhile p
xs == foldr (\x l' - if p x then l' else x:l')
Quoth Joel Reymont, nevermore,
Are these two different Simons? :-)
I'm beginning to wonder if Simon is less a name and more a title,
meaning strong in the lambda force or somesuch. Let's hope they don't
go over to the dark side ;-)
--
Dougal Stanton
[EMAIL PROTECTED] wrote:
Still, in the interest of purity, here it is, in
Haskell. As the original Eratosthenes sieve,
this algorithm uses only successor and
predecessor operations.
I don't think the Greeks had too much trouble with
addition. If that is the case, then Rafael's
definition is
Lennart Augustsson wrote:
I'm not sure what you're asking. The (untyped) lambda calculus is
Turing complete.
How could seq improve that?
Obviously, it can't. But how can it hurt?
Classical lambda calculus does not model the
semantics of laziness, so seq is equivalent to
flip const there,
Eric Willigers wrote:
Do the two programs implement the same algorithm? The C program updates
x and y in sequence. The Haskell program updates x and y in parallel and
can be easier for the compiler to optimize.
Hi Don,
Expressing this in other words, do we want the new y to be based on the
Hello Lennart,
Monday, February 12, 2007, 11:53:32 AM, you wrote:
Many architectures gives both the quotient and remainder when you use
the division instruction, so divMod (quotRem) shouldn't cost more
than a div or mod. But if the code generator takes advantage of that
is another matter.
Hello Matt,
Monday, February 12, 2007, 8:45:47 AM, you wrote:
I am trying to get a deeper understanding of core's role in GHC and
i'm not sure but may be these papers that say about STG can help you:
Implementing lazy functional languages on stock hardware: the
Spineless Tagless G-machine.
Hello Joel,
Monday, February 12, 2007, 12:23:16 PM, you wrote:
- Secrets of the Glasgow Haskell Compiler inliner.
Matt, can you please post pointers to the above?
mostly, these are available on papers pages of SM and SPJ:
http://research.microsoft.com/~simonpj/
On Monday 12 February 2007 09:54, Yitzchak Gale wrote:
Bulat Ziganshin wrote:
examples of lifting C functions into Haskell world:
mysin :: Double - Double
mysin = realToFrac . c_mysin . realToFrac
-- c_mysin :: CDouble - CDouble
rnd :: Int - IO Int
rnd x = do r - c_rnd
Hi,
I wanted to setup really simple http server, found Network.CGI.Compat.pwrapper
and decided it suits my needs. Code:
module Main where
import Network.CGI
import Text.XHtml
import Network
doit vars = do
return (body (toHtml (show vars)))
main = withSocketsDo (pwrapper (PortNumber )
Guess this is a tricky choice for a foldr intro, since it requires a
paramorphism (see bananas lenses wires etc.)
para :: (a - [a] - b - b) - b - [a] - b
para f e [] = e
para f e (x:xs) = f x xs (para f e xs)
-- note that the original tail of the list (i.e. xs and not xs') is
used in the
Hello,
the Advanced Monads page in the Haskell Wikibook
(http://en.wikibooks.org/wiki/Haskell/Advanced_monads) contains the following
example of a List Monad
pythags = do
x - [1..]
y - [x..]
z - [y..]
guard (x^2 + y^2 == z^2)
return (x, y, z)
However,
Check out Hoogle: http://haskell.org/hoogle/?q=guard
import Control.Monad
-Greg
On 2/12/07, [EMAIL PROTECTED] [EMAIL PROTECTED] wrote:
Hello,
the Advanced Monads page in the Haskell Wikibook
(http://en.wikibooks.org/wiki/Haskell/Advanced_monads) contains the
following
example of a List
On Feb 12, 2007, at 11:02 AM, [EMAIL PROTECTED] wrote:
Hello,
the Advanced Monads page in the Haskell Wikibook
(http://en.wikibooks.org/wiki/Haskell/Advanced_monads) contains the
following
example of a List Monad
pythags = do
x - [1..]
y - [x..]
z - [y..]
On 2/12/07, [EMAIL PROTECTED] [EMAIL PROTECTED] wrote:
Hello,
the Advanced Monads page in the Haskell Wikibook
(http://en.wikibooks.org/wiki/Haskell/Advanced_monads) contains the
following
example of a List Monad
pythags = do
x - [1..]
y - [x..]
z - [y..]
guard
On Feb 12, 2007, at 11:02 AM, [EMAIL PROTECTED] wrote:
Hello,
the Advanced Monads page in the Haskell Wikibook
(http://en.wikibooks.org/wiki/Haskell/Advanced_monads) contains the
following
example of a List Monad
pythags = do
x - [1..]
y - [x..]
z - [y..]
On 2/11/07, Matt Roberts [EMAIL PROTECTED] wrote:
- Exactly what are the operational and denotational semantics of core?
Since I don't think this question has been answered yet, here's a
mailing list post from Simon PJ that probably answers it:
On 2/12/07, Dougal Stanton [EMAIL PROTECTED] wrote:
Quoth Joel Reymont, nevermore,
Are these two different Simons? :-)
I'm beginning to wonder if Simon is less a name and more a title,
meaning strong in the lambda force or somesuch. Let's hope they don't
go over to the dark side ;-)
I
Nicolas Frisby wrote:
Guess this is a tricky choice for a foldr intro, since it requires a
paramorphism (see bananas lenses wires etc.)
para :: (a - [a] - b - b) - b - [a] - b
para f e [] = e
para f e (x:xs) = f x xs (para f e xs)
-- note that the original tail of the list (i.e. xs and not
Adding seq ruins eta reduction. For normal order lambda calculus
we have '\x.f x = f' (x not free in f). If we add seq this is no
longer true.
I'm not sure why you bring up lazy evaluation (I presume you
mean lazy evaluation as in call-by-need). Having call-by-need
or not is unobservable,
Oops; I totally forgot the context of this whole discussion!
I enjoyed your article.
On 2/12/07, Bernie Pope [EMAIL PROTECTED] wrote:
Nicolas Frisby wrote:
Guess this is a tricky choice for a foldr intro, since it requires a
paramorphism (see bananas lenses wires etc.)
para :: (a - [a] - b
Sure, but we also have
para f e xs = snd $ foldr (\ x ~(xs, y) - (x:xs, f x xs y)) ([], e) xs
So I think using para is fine.
-- Lennart
On Feb 12, 2007, at 18:40 , Bernie Pope wrote:
Nicolas Frisby wrote:
Guess this is a tricky choice for a foldr intro, since it requires a
On Feb 12, 2007, at 1:31 PM, Kirsten Chevalier wrote:
On 2/11/07, Matt Roberts [EMAIL PROTECTED] wrote:
- Exactly what are the operational and denotational semantics of
core?
Since I don't think this question has been answered yet, here's a
mailing list post from Simon PJ that probably
On Feb 12, 2007, at 14:22 , Gracjan Polak wrote:
I wanted to setup really simple http server, found
Network.CGI.Compat.pwrapper
and decided it suits my needs. Code:
module Main where
import Network.CGI
import Text.XHtml
import Network
doit vars = do
return (body (toHtml (show vars)))
Lennart Augustsson wrote:
Sure, but we also have
para f e xs = snd $ foldr (\ x ~(xs, y) - (x:xs, f x xs y)) ([], e) xs
Nice one.
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ewilligers:
Eric Willigers wrote:
Do the two programs implement the same algorithm? The C program updates
x and y in sequence. The Haskell program updates x and y in parallel and
can be easier for the compiler to optimize.
Hi Don,
Expressing this in other words, do we want the new y
On 2/12/07, Robert Dockins [EMAIL PROTECTED] wrote:
At the risk of sounding self-promoting, I'd like to point out that
the research paper I recently announced defines an intermediate
language that is similar to GHC's core in some respects (they are
both based on System F_omega). I give a full
On Tue, Feb 13, 2007 at 08:18:25AM +1100, Donald Bruce Stewart wrote:
Now, if we rewrite it to not use the temporary:
go :: Double - Double - Int - IO ()
go !x !y !i
| i == 10 = printf %.6f\n (x+y)
| otherwise = go (x*y/3) (x*9) (i+1)
for (;
Adding seq ruins eta reduction. For normal order lambda calculus
we have '\x.f x = f' (x not free in f). If we add seq this is no longer true.
isn't that a problem of seq (and evaluation in Haskell generally) not being
strict enough (ie, forcing evaluation only to weak head normal form
On 12/02/2007, at 8:23 PM, Joel Reymont wrote:
On Feb 12, 2007, at 5:45 AM, Matt Roberts wrote:
- The hackathon videos,
@electronic{hack06,
Author = {Simon Peyton Jones and Malcolm Wallace and et. al.},
Date-Added = {2007-02-13 09:04:47 +1100},
Date-Modified =
Bernie Pope wrote:
Lennart Augustsson wrote:
Sure, but we also have
para f e xs = snd $ foldr (\ x ~(xs, y) - (x:xs, f x xs y)) ([], e) xs
Nice one.
Nice one is an euphemism, it's exactly solution one :)
Regards,
apfelmus
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Arnaud Bailly wrote:
Joel Reymont wrote:
Is there a Java parser implemented using Parsec?
There is:
http://jparsec.codehaus.org/
Jparsec is an implementation of Haskell Parsec on the Java platform. I
think Joel was asking for a parser for the Java language, written in
Haskell using the
David Roundy wrote:
I'm rather curious (if you're sill interested) how this'll be affected by
the removal of the division from the inner loop. e.g.
go :: Double - Double - Int - IO ()
go !x !y !i
| i == 10 = printf %.6f\n (x+y)
| otherwise = go
Bjorn Bringert wrote:
pwrapper is not an HTTP server, though the Haddock comment can make you
think so. pwrapper allows you to talk *CGI* over a TCP port, but I have
no idea why anyone would like to do that.
Here is a scenerio. I want a basic web application: someone makes a
request, and my
On Mon, Feb 12, 2007 at 02:25:21PM -0800, Bryan O'Sullivan wrote:
David Roundy wrote:
I'm rather curious (if you're sill interested) how this'll be affected by
the removal of the division from the inner loop. e.g.
go :: Double - Double - Int - IO ()
go !x !y !i
| i ==
I thought solution one was missing the ~ ?
On Feb 12, 2007, at 22:07 , [EMAIL PROTECTED] wrote:
Bernie Pope wrote:
Lennart Augustsson wrote:
Sure, but we also have
para f e xs = snd $ foldr (\ x ~(xs, y) - (x:xs, f x xs y)) ([],
e) xs
Nice one.
Nice one is an euphemism, it's exactly
Hello,
Yes, I realize it's mid-February right now and the summer is still
months away, but it's probably not too early to think about the
future.
I am wondering if there are any Summer of Code projects that I would
be able to do for the Haskell community. I will be graduating from my
undergrad
No, I can't say off hand if seq-hnf would keep eta valid, either.
Neither do I know how to implement seq-hnf efficiently. :)
As far as eta for other types, yes, I'll take it if I can get it's
easily.
But I'm also pretty happy with encoding all the other data types within
the lambda calculus
bryan.burgers:
Hello,
Yes, I realize it's mid-February right now and the summer is still
months away, but it's probably not too early to think about the
future.
I am wondering if there are any Summer of Code projects that I would
be able to do for the Haskell community. I will be
We further simplify the previously posted genuine sieve algorithm and
generalize it to the finding of lucky numbers.
We observe that we only need to store marks _signifying_ the integers,
but never the integers themselves. Thus we arrive at the algorithm
that is distinguished from all
This little tool has been kicking around on my harddrive for a month or
two now, so time to release!
I'm pleased to announce the first release of urlcheck, an parallel link
checker, written in Haskell.
Frustrated with the resources and time consumed by 'linkchecker', when
preparing the weekly
Lennart Augustsson said:
Many architectures gives both the quotient and remainder when you use
the division instruction, so divMod (quotRem) shouldn't cost more
than a div or mod. But if the code generator takes advantage of that
is another matter.
You're quite right.
Bulat Ziganshin
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