Dear all,
I have a question about evaluation with respect to types and currying.
Consider this programm:
import Debug.Trace
-- add :: Integer - Integer - Integer
add :: Int - Int - Int
add x y = x + y
f a b c = trace b (add x c) where x = trace a (add a b)
main :: IO ()
main = do
print
Different kinds of optimization. I expect you'd have different results even if
you use one type, but different -O flags.
On 18 Feb 2012, at 13:28, Heinrich Hördegen wrote:
Dear all,
I have a question about evaluation with respect to types and currying.
Consider this programm:
import
Hi,
this is true. The optimization only works with -O2. I'd like to have
more details about what's going on. How can I make sure, that this
optimization triggers?
Heinrich
On 18.02.2012 11:10, MigMit wrote:
Different kinds of optimization. I expect you'd have different results even if
Hi Arnaud,
While not necessarily in line with the state of the art of FRP libraries, I can
warmly recommend going through the parts of Paul Hudak's Haskell School Of
Expression that cover the Functional Animation Library (FAL, basically a
light version of Fran).
The book introduces FRP
Am 18.02.2012 um 11:56 schrieb Heinrich Hördegen:
Hi,
this is true. The optimization only works with -O2. I'd like to have more
details about what's going on. How can I make sure, that this optimization
triggers?
You cannot. Common subexpression elimination is done by GHC very
As beginner I really liked reactive-banana. I used it in a inhouse
project for the graphical user interface (wx) and I found it easier to
use than the imperative approach. Unfortunately the
reactive-banana-wx package seems to be broken on 7.2.
On 2/18/12, Adam Duracz a...@duracz.net wrote:
Hi
+ on Int is extremely cheap. It is always faster to add again rather
than store the value.
But Integer is a different story. Addition time on this type can grow to
several minutes.
18.02.2012 13:28, Heinrich Hördegen пишет:
Dear all,
I have a question about evaluation with respect to types
In case of +, the reason might be that it's cheap, but the function add
could do something else than + (It was just a small example).
Ok, thank you for your useful comments. I will read about cse.
Heinrich
On 18.02.2012 13:42, Victor Gorokgov wrote:
+ on Int is extremely cheap. It is always
* Holger Siegel holgersiege...@yahoo.de [2012-02-18 12:52:08+0100]
You cannot. Common subexpression elimination is done by GHC very
conservatively, because it can not only affect impure programs: it can
also affects strictness/lazyness and worsen memory usage of pure code.
Like the HaskellWiki
Am 18.02.2012 um 14:38 schrieb Roman Cheplyaka:
* Holger Siegel holgersiege...@yahoo.de [2012-02-18 12:52:08+0100]
You cannot. Common subexpression elimination is done by GHC very
conservatively, because it can not only affect impure programs: it can
also affects strictness/lazyness
example = a + b + a + b
exampleCSE = x + x
where x = a + b
With CSE we are introducing new thunk: x.
18.02.2012 17:38, Roman Cheplyaka пишет:
* Holger Siegelholgersiege...@yahoo.de [2012-02-18 12:52:08+0100]
You cannot. Common subexpression elimination is done by GHC very
conservatively,
I'm not sure you can. Why do you need it?
Отправлено с iPad
18.02.2012, в 14:56, Heinrich Hördegen hoerde...@funktional.info написал(а):
Hi,
this is true. The optimization only works with -O2. I'd like to have more
details about what's going on. How can I make sure, that this optimization
Dear HC,
Does AFunctor below have a standard name? It's a generalization of
the Functor class in terms of Arrow instead of (-):
fmap :: Functor f = (i - o) - f i - f o
afmap :: Arrow a, AFunctor f = a i o- a (f i) (f o)
It pops up in less general form (AFunctor =
Thanks to all for your kind answers. I already installed reactive-banana
and skimmed through the doc which is quite good and extensive: at least
this is a good start. Should the need arise, I will not hesitate to tap
into the knowledge and wisdom of the community !
Regards,
Arnaud
It doesn't matter. Laziness would be affected if, for instance,
something is not evaluated without CSE and is evaluated with it.
In your example either all or none of 'a' and 'b' get evaluated,
depending on whether the top-level expression is evaluated.
* Victor Gorokgov m...@rkit.pp.ru
Hacky patch to fix this for future reference, against bytestring-csv-0.1.2,
cost center annotations used to anecdotally verify that the change doesn't
significantly impact performance, (interestingly the Alex lexer in
bytestring-csv appears to allocate 1.5GB while lexing a 1.6MB csv file!?)
Tom,
On 19/02/2012, at 3:21 AM, Tom Schouten wrote:
Does AFunctor below have a standard name? It's a generalization of
the Functor class in terms of Arrow instead of (-):
fmap :: Functor f = (i - o) - f i - f o
afmap :: Arrow a, AFunctor f = a i o- a (f i) (f o)
Hackage seems to be down:
http://www.downforeveryoneorjustme.com/http://hackage.haskell.org
Best,
Ozgur
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