Re: [Haskell-cafe] The C Equiv of != in Haskell miscommunication thread
Roberto Zunino wrote: I actually misread the first one as Control.Monad.Fix.fix ((1:) . tail . scanl (+) 1) which is quite nice too, although map (2^) [0..] would be much simpler! ;-) We apply a lesson learned from my last derivation. The lesson was to look at s!!(n+1). s = 1 : tail (scanl (+) 1 s) s!!(n+1) = (1 : tail (scanl (+) 1 s))!!(n+1) = tail (scanl (+) 1 s) !! n = scanl (+) 1 s !! (n+1) = 1 + s!!0 + s!!1 + s!!2 + ... + s!!n It turns out that we can generalize it a bit to s!!n = 1 + s!!0 + ... + s!!(n-1) since, in case n=0, it gives s!!0 = 1 + empty sum, which is still right. But now plugging the equation of s!!n into that of s!!(n+1) gives s!!(n+1) = 1 + s!!0 + s!!1 + s!!2 + ... s!!(n-1) + s!!n = s!!n + s!!n = 2 * s!!n Together with s!!0 = 1, this explains why s!!n = 2^n. ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] The C Equiv of != in Haskell miscommunication thread
Jason Dagit wrote: On 5/28/07, Donald Bruce Stewart <[EMAIL PROTECTED]> wrote: P.S. Have some cute code: Control.Monad.Fix.fix ((1:) . scanl (+) 1) Speaking of cute code, I'm fond of this: map length . List.group . Control.Monad.Fix.fix $ show Indeed, very nice examples! I actually misread the first one as Control.Monad.Fix.fix ((1:) . tail . scanl (+) 1) which is quite nice too, although map (2^) [0..] would be much simpler! ;-) Zun. ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] The C Equiv of != in Haskell miscommunication thread
On Tue, May 29, 2007 at 06:40:05PM -0700, Jason Dagit wrote: > Speaking of cute code, I'm fond of this: > > map length . List.group . Control.Monad.Fix.fix $ show "fix show" is cool in itself! :-) Best regards Tomek ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] The C Equiv of != in Haskell miscommunication thread
i would just like to say thank you for all the extensive replies. after fiddling with them for an afternoon i'm positive i grokked the concept. it's just too bad the nice wrapper concept from [1] does not seem to be directly applicable to fix in haskell, since they require untyped side-effects anyhow, this has been very instructive. thanks again! v. [1] http://citeseer.ist.psu.edu/mcadams01practical.html Jason Dagit wrote: > On 5/28/07, Donald Bruce Stewart <[EMAIL PROTECTED]> wrote: >> This thread should end, guys. It is inappropriate for the Haskell lists, >> and appears to have been a simple misunderstanding anyway. >> >> Thanks everyone. Please stay friendly! >> >> -- Don >> >> P.S. Have some cute code: >> >> Control.Monad.Fix.fix ((1:) . scanl (+) 1) > > Speaking of cute code, I'm fond of this: > > map length . List.group . Control.Monad.Fix.fix $ show > > And other (longer) variations which generate only powers of two. It's > a great conversation starter for teaching about fix. > > Jason > ___ > Haskell-Cafe mailing list > Haskell-Cafe@haskell.org > http://www.haskell.org/mailman/listinfo/haskell-cafe > > signature.asc Description: OpenPGP digital signature ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] The C Equiv of != in Haskell miscommunication thread
On 5/28/07, Donald Bruce Stewart <[EMAIL PROTECTED]> wrote: This thread should end, guys. It is inappropriate for the Haskell lists, and appears to have been a simple misunderstanding anyway. Thanks everyone. Please stay friendly! -- Don P.S. Have some cute code: Control.Monad.Fix.fix ((1:) . scanl (+) 1) Speaking of cute code, I'm fond of this: map length . List.group . Control.Monad.Fix.fix $ show And other (longer) variations which generate only powers of two. It's a great conversation starter for teaching about fix. Jason ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] The C Equiv of != in Haskell
On Tue, May 29, 2007 at 11:20:27AM +0100, David House wrote: > On 29/05/07, Daniel McAllansmith <[EMAIL PROTECTED]> wrote: > >Just in case there was some sort of miscommunication, the actual answer to > >your question is (/=) :: a -> a -> Bool, as Neil said. > > Almost, (/=) :: Eq a => a -> a. Almost again! (/=) :: Eq a => a -> a -> Bool Best regards Tomek ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] The C Equiv of != in Haskell
On 29/05/07, Antti-Juhani Kaijanaho <[EMAIL PROTECTED]> wrote: Well, not quite :) You forgot "-> Bool" at the end :) Ha! Sorry, what a lovely ironic typo. :) -- -David House, [EMAIL PROTECTED] ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] The C Equiv of != in Haskell
On Tue, May 29, 2007 at 11:20:27AM +0100, David House wrote: > Almost, (/=) :: Eq a => a -> a. Well, not quite :) You forgot "-> Bool" at the end :) > (Just for completeness.) Exactly :) -- Antti-Juhani Kaijanaho, Jyväskylä http://antti-juhani.kaijanaho.fi/newblog/ ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] The C Equiv of != in Haskell
On 29/05/07, Daniel McAllansmith <[EMAIL PROTECTED]> wrote: Just in case there was some sort of miscommunication, the actual answer to your question is (/=) :: a -> a -> Bool, as Neil said. Almost, (/=) :: Eq a => a -> a. (Just for completeness.) -- -David House, [EMAIL PROTECTED] ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] The C Equiv of != in Haskell miscommunication thread
kahl: > > > > P.S. Have some cute code: > > > > Control.Monad.Fix.fix ((1:) . scanl (+) 1) > > > Cute! > > But what an un-cute qualified name: > > :t Control.Monad.Fix.fix > Control.Monad.Fix.fix :: (a -> a) -> a > > > Has nothing to do with monads, > and would perhaps be considered as ``out of Control'' in any case... > I see it has moved into Data.Function, module Data.Function ( -- * "Prelude" re-exports id, const, (.), flip, ($) -- * Other combinators , fix , on ) where A much better place. -- Don ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] The C Equiv of != in Haskell miscommunication thread
> > P.S. Have some cute code: > > Control.Monad.Fix.fix ((1:) . scanl (+) 1) Cute! But what an un-cute qualified name: :t Control.Monad.Fix.fix Control.Monad.Fix.fix :: (a -> a) -> a Has nothing to do with monads, and would perhaps be considered as ``out of Control'' in any case... ;-) Wolfram ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] The C Equiv of != in Haskell (Apologies)
On 5/29/07, PR Stanley <[EMAIL PROTECTED]> wrote: Yet, you seem to be desperate to keep the thread alive. As long as I'm personally attacked. But whatever, let's forget about it, you already said it's been a bad day. End of flamebait ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] The C Equiv of != in Haskell miscommunication thread
This thread should end, guys. It is inappropriate for the Haskell lists, and appears to have been a simple misunderstanding anyway. Thanks everyone. Please stay friendly! -- Don P.S. Have some cute code: Control.Monad.Fix.fix ((1:) . scanl (+) 1) ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] The C Equiv of != in Haskell (Apologies)
However, I don't think these other individuals had any business poking their hooters into this. If you don't want other individuals "poking their hooters" in what you write, I recommend you to avoid sending open questions to public mailing lists. yes, I was indeed referring to you and your large beak over which you clearly have no control. Nobody invited you to this discussion and as you can see I have already apologized to Neil for the misunderstanding. Yet, you seem to be desperate to keep the thread alive. Uh, save me from the ... ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] The C Equiv of != in Haskell
Thank you Neil, again I'm sorry for getting the wrong end of the stick. Cheers Paul At 02:50 29/05/2007, you wrote: Hi Paul Sorry if you interpreted my answer as a symbol, I never use smilies so didn't even consider that people may see it in another light! Thanks Neil On 5/29/07, PR Stanley <[EMAIL PROTECTED]> wrote: > > >Hi > > > > > >>What is the C equivalent of the inequality operator in Haskell? > > > > > >/= > > > > > >You can answer these sorts of questions yourself using Hoogle: > > > > And what makes you think I haven't tried Google already? > > Unlike you I only write to the list when I have a legitimate reason to do > > so. > >Just in case there was some sort of miscommunication, the actual answer to >your question is (/=) :: a -> a -> Bool, as Neil said. > >The /= wasn't some sort of frowny, quit-wasting-my-time emoticon. >___ Thank you, Dan. Regards Paul ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] The C Equiv of != in Haskell (Apologies)
On 5/29/07, PR Stanley <[EMAIL PROTECTED]> wrote: However, I don't think these other individuals had any business poking their hooters into this. If you don't want other individuals "poking their hooters" in what you write, I recommend you to avoid sending open questions to public mailing lists. ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] The C Equiv of != in Haskell
At 03:02 29/05/2007, you wrote: On 5/29/07, PR Stanley <[EMAIL PROTECTED]> wrote: What is this, the Haskell Cafe Gang? Maybe. Moreover this list is not a prepaid service in which you can unpolitely _demand_ answers. You got your question answered still complain ... I don't get it. Yes, the question has been answered but you still feel the need to keep the thread alive, hmm, you're right, it is very strange behaviour indeed. ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] The C Equiv of != in Haskell (Apologies)
Hi >You can answer these sorts of questions yourself using Hoogle: And what makes you think I haven't tried Google already? Hoogle, starting with 'H'. Follow the link I gave you, which is a search engine for Haskell functions, by type and name. If you search for "a -> a -> Bool" (a likely type that the != would have) then Hoogle gives you an answer. Unlike you I only write to the list when I have a legitimate reason to do so. I am not suggesting you have no legitimate reason, just trying to help you find the information you need quicker in future. I was in no way trying to suggest you shouldn't have posted - its a fair question given its a different choice to most other languages. Thanks Neil Thank you,Neil. I apologise for my sharp response. It's been a long day. However, I don't think these other individuals had any business poking their hooters into this. All the best, Paul ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] The C Equiv of != in Haskell
On 5/29/07, PR Stanley <[EMAIL PROTECTED]> wrote: What is this, the Haskell Cafe Gang? Maybe. Moreover this list is not a prepaid service in which you can unpolitely _demand_ answers. You got your question answered still complain ... I don't get it. ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] The C Equiv of != in Haskell
At 02:27 29/05/2007, you wrote: PR Stanley wrote: Hi What is the C equivalent of the inequality operator in Haskell? /= You can answer these sorts of questions yourself using Hoogle: And what makes you think I haven't tried Google already? Unlike you I only write to the list when I have a legitimate reason to do so. Apparently, unlike him, you don't read the emails. He answered your question, gave you one way of answering all such future question (note Hoogle /= Google), and finally, there are certainly other places you could look before writing to the list that would answer your question, e.g. the Report. and you can mind your own damn business. What is this, the Haskell Cafe Gang? ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] The C Equiv of != in Haskell
> >Hi > > > >>What is the C equivalent of the inequality operator in Haskell? > > > >/= > > > >You can answer these sorts of questions yourself using Hoogle: > > And what makes you think I haven't tried Google already? > Unlike you I only write to the list when I have a legitimate reason to do > so. Just in case there was some sort of miscommunication, the actual answer to your question is (/=) :: a -> a -> Bool, as Neil said. The /= wasn't some sort of frowny, quit-wasting-my-time emoticon. ___ Thank you, Dan. Regards Paul ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] The C Equiv of != in Haskell
At 02:26 29/05/2007, you wrote: PR Stanley wrote: > >> Hi >> >>> What is the C equivalent of the inequality operator in Haskell? >> >> /= >> >> You can answer these sorts of questions yourself using Hoogle: > And what makes you think I haven't tried Google already? > Unlike you I only write to the list when I have a legitimate reason to > do so. The respondent said HHHoogle, not Google, and rightly so. Did you take a look at the given link? Here it is again http://www.haskell.org/hoogle/?q=a%20-%3E%20a%20-%3E%20Bool Hold onto that jerky knee! It's a sort of natural reaction to self-righteous jerks. Of course, a simple reply to the initial question would have been far too convenient. ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] The C Equiv of != in Haskell
On Tuesday 29 May 2007 13:20, PR Stanley wrote: > >Hi > > > >>What is the C equivalent of the inequality operator in Haskell? > > > >/= > > > >You can answer these sorts of questions yourself using Hoogle: > > And what makes you think I haven't tried Google already? > Unlike you I only write to the list when I have a legitimate reason to do > so. Just in case there was some sort of miscommunication, the actual answer to your question is (/=) :: a -> a -> Bool, as Neil said. The /= wasn't some sort of frowny, quit-wasting-my-time emoticon. ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] The C Equiv of != in Haskell
PR Stanley wrote: Hi What is the C equivalent of the inequality operator in Haskell? /= You can answer these sorts of questions yourself using Hoogle: And what makes you think I haven't tried Google already? Unlike you I only write to the list when I have a legitimate reason to do so. Apparently, unlike him, you don't read the emails. He answered your question, gave you one way of answering all such future question (note Hoogle /= Google), and finally, there are certainly other places you could look before writing to the list that would answer your question, e.g. the Report. ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] The C Equiv of != in Haskell
Hi >You can answer these sorts of questions yourself using Hoogle: And what makes you think I haven't tried Google already? Hoogle, starting with 'H'. Follow the link I gave you, which is a search engine for Haskell functions, by type and name. If you search for "a -> a -> Bool" (a likely type that the != would have) then Hoogle gives you an answer. Unlike you I only write to the list when I have a legitimate reason to do so. I am not suggesting you have no legitimate reason, just trying to help you find the information you need quicker in future. I was in no way trying to suggest you shouldn't have posted - its a fair question given its a different choice to most other languages. Thanks Neil ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] The C Equiv of != in Haskell
PR Stanley wrote: > >> Hi >> >>> What is the C equivalent of the inequality operator in Haskell? >> >> /= >> >> You can answer these sorts of questions yourself using Hoogle: > And what makes you think I haven't tried Google already? > Unlike you I only write to the list when I have a legitimate reason to > do so. > > ___ > Haskell-Cafe mailing list > Haskell-Cafe@haskell.org > http://www.haskell.org/mailman/listinfo/haskell-cafe > > > The respondent said HHHoogle, not Google, and rightly so. Did you take a look at the given link? Here it is again http://www.haskell.org/hoogle/?q=a%20-%3E%20a%20-%3E%20Bool Hold onto that jerky knee! Tony Morris http://tmorris.net/ signature.asc Description: OpenPGP digital signature ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] The C Equiv of != in Haskell
Hi What is the C equivalent of the inequality operator in Haskell? /= You can answer these sorts of questions yourself using Hoogle: And what makes you think I haven't tried Google already? Unlike you I only write to the list when I have a legitimate reason to do so. ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] The C Equiv of != in Haskell
Hi What is the C equivalent of the inequality operator in Haskell? /= You can answer these sorts of questions yourself using Hoogle: http://www.haskell.org/hoogle/?q=a%20-%3E%20a%20-%3E%20Bool Thanks Neil ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] The C Equiv of != in Haskell
Hi What is the C equivalent of the inequality operator in Haskell? Thanks Paul ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
