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You can reach the person managing the list at beginners-ow...@haskell.org When replying, please edit your Subject line so it is more specific than "Re: Contents of Beginners digest..." Today's Topics: 1. question (Roelof Wobben) 2. Re: question (Adrien Haxaire) 3. question (Roelof Wobben) 4. Re: question (Kyle Murphy) 5. Re: question (Andres Loeh) 6. Re: Monads in javascript (Martin Drautzburg) 7. FW: question (Roelof Wobben) 8. Re: Monads in javascript (Mats Rauhala) 9. Re: Monads in javascript (Thomas Davie) 10. Re: FW: question (Luca Ciciriello) ---------------------------------------------------------------------- Message: 1 Date: Wed, 13 Jul 2011 19:27:41 +0000 From: Roelof Wobben <rwob...@hotmail.com> Subject: [Haskell-beginners] question To: <beginners@haskell.org> Message-ID: <snt118-w15151ddd66694f8bb57c2cae...@phx.gbl> Content-Type: text/plain; charset="iso-8859-1" hello, For a exercise I need to multiply a number by itself. So I used : [x^2 | x <- [1..100]] but now I get a error message on codepad that ^is unknown. What can I use then and where do I find it on a keyboard? Roelof ------------------------------ Message: 2 Date: Wed, 13 Jul 2011 22:00:40 +0200 From: Adrien Haxaire <adr...@adrienhaxaire.org> Subject: Re: [Haskell-beginners] question To: Haskell Beginners <beginners@haskell.org> Message-ID: <4e1df968.4090...@adrienhaxaire.org> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Le 13/07/2011 21:27, Roelof Wobben a ?crit : > For a exercise I need to multiply a number by itself. > > So I used : > > > > [x^2 | x<- [1..100]] > > but now I get a error message on codepad that ^is unknown. > What can I use then and where do I find it on a keyboard? > > Roelof Hello, What does codepad not recognize? the caret character or the expression you used? ghci 7.0.3 gives me this: Prelude> [x**2 | x <- [1..10]] [1.0,4.0,9.0,16.0,25.0,36.0,49.0,64.0,81.0,100.0] Prelude> [x^2 | x <- [1..10]] [1,4,9,16,25,36,49,64,81,100] Did you try it on ghci or in a text file? I guess we need more details if the former. Which version of ghci do you have? What is your OS? Regards, Adrien ------------------------------ Message: 3 Date: Wed, 13 Jul 2011 20:09:00 +0000 From: Roelof Wobben <rwob...@hotmail.com> Subject: [Haskell-beginners] question To: <beginners@haskell.org> Message-ID: <snt118-w2308ccb9c6909a4f7e0a45ae...@phx.gbl> Content-Type: text/plain; charset="iso-8859-1" ---------------------------------------- > From: rwob...@hotmail.com > To: adr...@adrienhaxaire.org > Subject: RE: [Haskell-beginners] question > Date: Wed, 13 Jul 2011 20:07:54 +0000 > > > > > ---------------------------------------- > > Date: Wed, 13 Jul 2011 22:00:40 +0200 > > From: adr...@adrienhaxaire.org > > To: beginners@haskell.org > > Subject: Re: [Haskell-beginners] question > > > > Le 13/07/2011 21:27, Roelof Wobben a ?crit : > > > For a exercise I need to multiply a number by itself. > > > > > > So I used : > > > > > > > > > > > > [x^2 | x<- [1..100]] > > > > > > but now I get a error message on codepad that ^is unknown. > > > What can I use then and where do I find it on a keyboard? > > > > > > Roelof > > > > Hello, > > > > What does codepad not recognize? the caret character or the expression > > you used? > It don't regonize the caret character, Like I said I use www.codepad.org and it uses Hugs. Roelof ------------------------------ Message: 4 Date: Wed, 13 Jul 2011 16:32:38 -0400 From: Kyle Murphy <orc...@gmail.com> Subject: Re: [Haskell-beginners] question To: Roelof Wobben <rwob...@hotmail.com> Cc: beginners@haskell.org Message-ID: <CA+y6Jcy93iTo8Aezn-Rt=ub_k9nhgk8b9modmvjeeyofffs...@mail.gmail.com> Content-Type: text/plain; charset="utf-8" If you're going to continue to use www.codepad.org it might be worthwhile to download and install Hugs so you have a better idea of what is and isn't supported by it. That being said, I wouldn't use codepad.org, or Hugs, as Hugs is rather out of date and GHC is much better. In addition to being more up to date, GHC is also used by most Haskell developers, including I'd imagine nearly everyone on this mailing list, so you're going to get much better feedback about it versus Hugs. -R. Kyle Murphy -- Curiosity was framed, Ignorance killed the cat. On Wed, Jul 13, 2011 at 16:09, Roelof Wobben <rwob...@hotmail.com> wrote: > > > > ---------------------------------------- > > From: rwob...@hotmail.com > > To: adr...@adrienhaxaire.org > > Subject: RE: [Haskell-beginners] question > > Date: Wed, 13 Jul 2011 20:07:54 +0000 > > > > > > > > > > ---------------------------------------- > > > Date: Wed, 13 Jul 2011 22:00:40 +0200 > > > From: adr...@adrienhaxaire.org > > > To: beginners@haskell.org > > > Subject: Re: [Haskell-beginners] question > > > > > > Le 13/07/2011 21:27, Roelof Wobben a ?crit : > > > > For a exercise I need to multiply a number by itself. > > > > > > > > So I used : > > > > > > > > > > > > > > > > [x^2 | x<- [1..100]] > > > > > > > > but now I get a error message on codepad that ^is unknown. > > > > What can I use then and where do I find it on a keyboard? > > > > > > > > Roelof > > > > > > Hello, > > > > > > What does codepad not recognize? the caret character or the expression > > > you used? > > > > > It don't regonize the caret character, > > Like I said I use www.codepad.org and it uses Hugs. > > Roelof > > > > > > _______________________________________________ > Beginners mailing list > Beginners@haskell.org > http://www.haskell.org/mailman/listinfo/beginners > -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://www.haskell.org/pipermail/beginners/attachments/20110713/819bef06/attachment-0001.htm> ------------------------------ Message: 5 Date: Wed, 13 Jul 2011 23:04:58 +0200 From: Andres Loeh <andres.l...@googlemail.com> Subject: Re: [Haskell-beginners] question To: beginners@haskell.org Message-ID: <CALjd_v5gcySr=wnf5drl+3uq9_r4pagannxfmhgjn12tc-w...@mail.gmail.com> Content-Type: text/plain; charset=ISO-8859-1 I've just tried to evaluate 2 ^ 5 in codepad and it worked for me, so (^) seems to be supported. Cheers, Andres ------------------------------ Message: 6 Date: Wed, 13 Jul 2011 23:18:04 +0200 From: Martin Drautzburg <martin.drautzb...@web.de> Subject: Re: [Haskell-beginners] Monads in javascript To: beginners@haskell.org Message-ID: <201107132318.04255.martin.drautzb...@web.de> Content-Type: Text/Plain; charset="iso-8859-1" On Wednesday, 13. July 2011 00:03:44 Ertugrul Soeylemez wrote: > > I had some hopes that chaining functions monad-style would ease my > > pain. I might be on the wrong track though, feel free to tell me so. > > You probably are, because the usefulness of monads depends a good deal > on syntax. ECMA-based languages like JavaScript, ActionScript, Haxe, > etc. have a terrible syntax for anonymous functions. > > To give you an alternative, this really sounds like you're looking for a > continuation-based solution. Continuation passing style could really > solve your problem elegantly even in JavaScript. Right. It did. It sometimes doens't work to define the callback *after* the function which needs the callback. It is not always easy to find out *when* things need to be defined in javascript. Luckily in Haskell there is no "when". Still in most cases it works and the code looks like regular procedural code, where control flows from top to bottom. And I could nicely write code where the callback makes another callback etc. Thanks. -- Martin ------------------------------ Message: 7 Date: Thu, 14 Jul 2011 07:55:30 +0000 From: Roelof Wobben <rwob...@hotmail.com> Subject: [Haskell-beginners] FW: question To: <beginners@haskell.org> Message-ID: <snt118-w25aca8f008c3d1fa3e34b7ae...@phx.gbl> Content-Type: text/plain; charset="iso-8859-1" Oke, I tried with Ghci 7.03 on the prompt but then I see this: [x^2 | x <-- [1..100] not in scope x not in scope <-- When I put the text in a file I see these errors. parse error : naked expression at top level. Roelof > > > > ---------------------------------------- > > Date: Wed, 13 Jul 2011 23:04:58 +0200 > > From: andres.l...@googlemail.com > > To: beginners@haskell.org > > Subject: Re: [Haskell-beginners] question > > > > I've just tried to evaluate 2 ^ 5 in codepad and it worked for me, so > > (^) seems to be supported. > > > > Cheers, > > Andres > > > > _______________________________________________ > > Beginners mailing list > > Beginners@haskell.org > > http://www.haskell.org/mailman/listinfo/beginners > > ------------------------------ Message: 8 Date: Thu, 14 Jul 2011 11:03:23 +0300 From: Mats Rauhala <mats.rauh...@gmail.com> Subject: Re: [Haskell-beginners] Monads in javascript To: beginners@haskell.org Message-ID: <20110714080323.GA4959@libre.local> Content-Type: text/plain; charset="us-ascii" On 23:18 Wed 13 Jul , Martin Drautzburg wrote: > Right. It did. > > It sometimes doens't work to define the callback *after* the function which > needs the callback. It is not always easy to find out *when* things need to > be > defined in javascript. Luckily in Haskell there is no "when". > > Still in most cases it works and the code looks like regular procedural code, > where control flows from top to bottom. And I could nicely write code where > the callback makes another callback etc. > > Thanks. Could you give an example how CPS helped your situation? I'm trying to grok continuation passing style, but for now it just seems to complicate and/or slow down code (stack) -- Mats Rauhala MasseR -------------- next part -------------- A non-text attachment was scrubbed... Name: not available Type: application/pgp-signature Size: 198 bytes Desc: not available URL: <http://www.haskell.org/pipermail/beginners/attachments/20110714/957b771c/attachment-0001.pgp> ------------------------------ Message: 9 Date: Thu, 14 Jul 2011 09:13:10 +0100 From: Thomas Davie <tom.da...@gmail.com> Subject: Re: [Haskell-beginners] Monads in javascript To: Mats Rauhala <mats.rauh...@gmail.com> Cc: beginners@haskell.org Message-ID: <deb0924c-96d6-481c-a15f-d26038b7e...@gmail.com> Content-Type: text/plain; charset=windows-1252 On 14 Jul 2011, at 09:03, Mats Rauhala wrote: > Could you give an example how CPS helped your situation? I'm trying to > grok continuation passing style, but for now it just seems to complicate > and/or slow down code (stack) This obviously isn't Martin's example, but hopefully this should help. In a 3D game engine, the norm (in procedural land at least) is to have calls like someInWorldObject.animate(someAnimation). If you want to run that animation, and then another, the norm is to set a timer to fire when the animation is complete and to call another call like that. My engine by comparison uses CPS ? whenever you ask the engine to run an animation of some kind you must specify either a) that it repeats indefinitely, or b) has a continuation to deal with what happens after that animation is complete. The result is that calling code doesn't have random timers floating around, and can define what happens at the completion of an animation in a closure, inline with creating that animation. Apple's CoreAnimation also uses continuation passing style for a similar purpose. Both of these examples use CPS because it allows things to happen asynchronously ? an animation can disappear off and run, and then something come back to you once it's finished. I have also found CPS can clean up synchronous code too. Take a look at CPBrainfuck on hackage ? I personally think it's one of the cleaner implementations of BF out there, though I will freely admit it's not the fastest. Thanks Tom Davie ------------------------------ Message: 10 Date: Thu, 14 Jul 2011 10:16:33 +0200 From: Luca Ciciriello <luca_cicirie...@hotmail.com> Subject: Re: [Haskell-beginners] FW: question To: Roelof Wobben <rwob...@hotmail.com> Cc: beginners@haskell.org Message-ID: <blu0-smtp6793e369a5fad556c102c69a...@phx.gbl> Content-Type: text/plain; charset="us-ascii" Hi. On wich system are you using GHCi ? Probably I missed this information from the previous mail. I'm using GHC 7.0.4 on MacOS X 10.6.8 (Xcode 4) and all works fine with [x^2 | x <- [1..10]]. You can try to see if you installation of ghc is ok typing "ghc-pkg list" from a console, or using the command ghc -v to see if there are some strange notification. Luca. On Jul 14, 2011, at 9:55 AM, Roelof Wobben wrote: > > Oke, > > > I tried with Ghci 7.03 on the prompt but then I see this: > > > [x^2 | x <-- [1..100] > > > not in scope x > not in scope <-- > > > When I put the text in a file I see these errors. > > > parse error : naked expression at top level. > > > Roelof > > >> >> >> >> ---------------------------------------- >>> Date: Wed, 13 Jul 2011 23:04:58 +0200 >>> From: andres.l...@googlemail.com >>> To: beginners@haskell.org >>> Subject: Re: [Haskell-beginners] question >>> >>> I've just tried to evaluate 2 ^ 5 in codepad and it worked for me, so >>> (^) seems to be supported. >>> >>> Cheers, >>> Andres >>> >>> _______________________________________________ >>> Beginners mailing list >>> Beginners@haskell.org >>> http://www.haskell.org/mailman/listinfo/beginners >>> > _______________________________________________ > Beginners mailing list > Beginners@haskell.org > http://www.haskell.org/mailman/listinfo/beginners > ------------------------------ _______________________________________________ Beginners mailing list Beginners@haskell.org http://www.haskell.org/mailman/listinfo/beginners End of Beginners Digest, Vol 37, Issue 26 *****************************************