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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. Re: cmath Install troubles (Brandon Allbery) 2. Re: Seq question (Tim Perry) 3. Re: Seq question (Daniel Fischer) 4. Re: cmath Install troubles (Tom Murphy) 5. Two questions for a production project... (Mike Meyer) 6. Re: cmath Install troubles (Tom Murphy) 7. Re: Two questions for a production project... (Michael Orlitzky) ---------------------------------------------------------------------- Message: 1 Date: Thu, 19 Apr 2012 16:31:33 -0400 From: Brandon Allbery <allber...@gmail.com> Subject: Re: [Haskell-beginners] cmath Install troubles To: Tom Murphy <amin...@gmail.com> Cc: beginners <beginners@haskell.org> Message-ID: <CAKFCL4WSHJz9Vn6t1cc_5QU67j=immuscgczfujlawkobk8...@mail.gmail.com> Content-Type: text/plain; charset="utf-8" On Thu, Apr 19, 2012 at 06:31, Tom Murphy <amin...@gmail.com> wrote: > So does nobody use cmath anymore? I'm trying to install the latest > version (which is from 2008). At a guess, it's well supported on Linux and (since it's dons) NetBSD. OS X and Windows, probably not so well tested. -- brandon s allbery allber...@gmail.com wandering unix systems administrator (available) (412) 475-9364 vm/sms -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://www.haskell.org/pipermail/beginners/attachments/20120419/09d82b8a/attachment-0001.htm> ------------------------------ Message: 2 Date: Thu, 19 Apr 2012 14:13:48 -0700 From: Tim Perry <tim.v...@gmail.com> Subject: Re: [Haskell-beginners] Seq question To: beginners@haskell.org Message-ID: <CAFVgASUyEfyRbarCpSUQfAPz1wCmdEPTk09DSp7b6Oc=xk1...@mail.gmail.com> Content-Type: text/plain; charset="iso-8859-1" Henk-Jan van Tuly is correct. Oops! Sorry I was mis-informed. By the way, there is an excellent post about this topic on StackOverflow.com. It covers, seq, weak-head-normal-form, normal form, and thunks. See here: http://stackoverflow.com/questions/6872898/haskell-what-is-weak-head-normal-form/6889335#6889335 Hope that makes up for my earlier comment. Tim On Thu, Apr 19, 2012 at 2:31 AM, Henk-Jan van Tuyl <hjgt...@chello.nl>wrote: > On Wed, 18 Apr 2012 16:45:05 +0200, Brent Yorgey <byor...@seas.upenn.edu> > wrote: > > On Tue, Apr 17, 2012 at 02:41:15PM -0700, Tim Perry wrote: >> >>> seq evaluates to Weak Head Normal Form (WHNF). WHNF is the first >>> contructor. So your use of seq only evaluates the first number and the >>> cons. I.E., it evaluates to: >>> s:(Thunk) >>> >> >> Actually, it doesn't even force the first number. You just get >> >> Thunk : Thunk >> >> > A nice way to demonstrate this, is the following GHCi session: > Prelude> undefined `seq` print "OK" > *** Exception: Prelude.undefined > Prelude> [undefined] `seq` print "OK" > "OK" > > > Regards, > Henk-Jan van Tuyl > > > -- > http://Van.Tuyl.eu/ > http://members.chello.nl/**hjgtuyl/tourdemonad.html<http://members.chello.nl/hjgtuyl/tourdemonad.html> > Haskell programming > -- > > > ______________________________**_________________ > Beginners mailing list > Beginners@haskell.org > http://www.haskell.org/**mailman/listinfo/beginners<http://www.haskell.org/mailman/listinfo/beginners> > -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://www.haskell.org/pipermail/beginners/attachments/20120419/7747d7bd/attachment-0001.htm> ------------------------------ Message: 3 Date: Fri, 20 Apr 2012 00:23:22 +0200 From: Daniel Fischer <daniel.is.fisc...@googlemail.com> Subject: Re: [Haskell-beginners] Seq question To: beginners@haskell.org Message-ID: <201204200023.22171.daniel.is.fisc...@googlemail.com> Content-Type: Text/Plain; charset="utf-8" On Thursday 19 April 2012, 23:13:48, Tim Perry wrote: > Henk-Jan van Tuly is correct. Oops! Sorry I was mis-informed. Note, however, that in the case here, the data-dependencies force the evaluation of the first number in order to determine the outermost constructor. So actually, your > So your use of seq only evaluates the first number and > the cons. I.E., it evaluates to: > s:(Thunk) was factually correct (in this special case). > By the > way, there is an excellent post about this topic on StackOverflow.com. > It covers, seq, weak-head-normal-form, normal form, and thunks. See > here: > http://stackoverflow.com/questions/6872898/haskell-what-is-weak-head-no > rmal-form/6889335#6889335 > > > Hope that makes up for my earlier comment. > > Tim > > On Thu, Apr 19, 2012 at 2:31 AM, Henk-Jan van Tuyl <hjgt...@chello.nl>wrote: > > On Wed, 18 Apr 2012 16:45:05 +0200, Brent Yorgey > > <byor...@seas.upenn.edu> > > > > wrote: > > On Tue, Apr 17, 2012 at 02:41:15PM -0700, Tim Perry wrote: > >>> seq evaluates to Weak Head Normal Form (WHNF). WHNF is the first > >>> contructor. So your use of seq only evaluates the first number and > >>> the cons. I.E., it evaluates to: > >>> s:(Thunk) > >> > >> Actually, it doesn't even force the first number. You just get > >> > >> Thunk : Thunk > > > > A nice way to demonstrate this, is the following GHCi session: > > Prelude> undefined `seq` print "OK" > > *** Exception: Prelude.undefined > > Prelude> [undefined] `seq` print "OK" > > "OK" > > > > Regards, > > Henk-Jan van Tuyl ------------------------------ Message: 4 Date: Thu, 19 Apr 2012 18:29:39 -0400 From: Tom Murphy <amin...@gmail.com> Subject: Re: [Haskell-beginners] cmath Install troubles To: Brandon Allbery <allber...@gmail.com> Cc: beginners <beginners@haskell.org> Message-ID: <cao9q0tvzxtsj_bf5hpul5g5ojyxcuq-vhzzu9wd3gixzx0g...@mail.gmail.com> Content-Type: text/plain; charset=ISO-8859-1 cmath doesn't build now, but I successfully installed hsc3 (which depends on cmath) on my computer less than 6 months ago. Same CPU and OS version, but different ghc/HP, and possibly different XCode. Also: Some other packages which have the same FFI C-include style build fine on my machine. Some which even include math.h. For example: - strptime - mp3decoder So maybe it's not a problem involving not having -fvia-c? Tom On 4/19/12, Brandon Allbery <allber...@gmail.com> wrote: > On Thu, Apr 19, 2012 at 06:31, Tom Murphy <amin...@gmail.com> wrote: > >> So does nobody use cmath anymore? I'm trying to install the latest >> version (which is from 2008). > > > At a guess, it's well supported on Linux and (since it's dons) NetBSD. OS > X and Windows, probably not so well tested. > > -- > brandon s allbery allber...@gmail.com > wandering unix systems administrator (available) (412) 475-9364 vm/sms > ------------------------------ Message: 5 Date: Thu, 19 Apr 2012 19:40:02 -0400 From: Mike Meyer <m...@mired.org> Subject: [Haskell-beginners] Two questions for a production project... To: beginners@haskell.org <beginners@haskell.org> Message-ID: <20120419194002.6f155...@bhuda.mired.org> Content-Type: text/plain; charset=US-ASCII I've got a project coming up that I could use haskell for, providing I can convince myself that it's appropriate. The critical question is: Anyone using Haskell in a long-running production application? I'm talking about something where the program would run for weeks or months non-stop, with either multiple threads or multiple copies. <mike -- Mike Meyer <m...@mired.org> http://www.mired.org/ Independent Software developer/SCM consultant, email for more information. O< ascii ribbon campaign - stop html mail - www.asciiribbon.org ------------------------------ Message: 6 Date: Thu, 19 Apr 2012 22:03:18 -0400 From: Tom Murphy <amin...@gmail.com> Subject: Re: [Haskell-beginners] cmath Install troubles To: Brandon Allbery <allber...@gmail.com> Cc: beginners <beginners@haskell.org> Message-ID: <CAO9Q0tUq+UorWfmTNFf=Am=kt4kq1hrlf1f61ezazitajet...@mail.gmail.com> Content-Type: text/plain; charset=ISO-8859-1 Also, is there a way that I could "short circuit" (in the "True || _ = True" sense) the whole process of fixing this? For example, cabal-install cmath on a machine with similar architecture and OS, break out my SICP [0], and try to replicate cabal's storage methods by hand? Tom [0] http://www.vex.net/~trebla/haskell/sicp.xhtml On 4/19/12, Tom Murphy <amin...@gmail.com> wrote: > cmath doesn't build now, but I successfully installed hsc3 (which > depends on cmath) on my computer less than 6 months ago. Same CPU and > OS version, but different ghc/HP, and possibly different XCode. > > Also: > > Some other packages which have the same FFI C-include style build fine > on my machine. Some which even include math.h. For example: > - strptime > - mp3decoder > > So maybe it's not a problem involving not having -fvia-c? > > > Tom > > On 4/19/12, Brandon Allbery <allber...@gmail.com> wrote: >> On Thu, Apr 19, 2012 at 06:31, Tom Murphy <amin...@gmail.com> wrote: >> >>> So does nobody use cmath anymore? I'm trying to install the latest >>> version (which is from 2008). >> >> >> At a guess, it's well supported on Linux and (since it's dons) NetBSD. >> OS >> X and Windows, probably not so well tested. >> >> -- >> brandon s allbery >> allber...@gmail.com >> wandering unix systems administrator (available) (412) 475-9364 >> vm/sms >> > ------------------------------ Message: 7 Date: Thu, 19 Apr 2012 22:43:13 -0400 From: Michael Orlitzky <mich...@orlitzky.com> Subject: Re: [Haskell-beginners] Two questions for a production project... To: beginners@haskell.org Message-ID: <4f90cd41.2010...@orlitzky.com> Content-Type: text/plain; charset=ISO-8859-1 On 04/19/2012 07:40 PM, Mike Meyer wrote: > I've got a project coming up that I could use haskell for, providing I > can convince myself that it's appropriate. The critical question is: > > Anyone using Haskell in a long-running production application? I'm > talking about something where the program would run for weeks or > months non-stop, with either multiple threads or multiple copies. I have a rather stupid application that parses feeds from the Twitter API. For each username given on the command line, it calls forkIO and the new thread enters a recursive loop: recurse x y z = do ... recurse x y z forever and ever. Contrary to my expectations (I still basically don't know what I'm doing in Haskell) it seems to run in constant space for months at a time. ------------------------------ _______________________________________________ Beginners mailing list Beginners@haskell.org http://www.haskell.org/mailman/listinfo/beginners End of Beginners Digest, Vol 46, Issue 35 *****************************************