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RE: zips and maps
by Conal Elliott 09 Mar '01

09 Mar '01

Note also that zipMap is the classic S combinatory if you think of lists as functions over the natural numbers, so there's something especially compelling about it. Similarly, repeat is K. From zipMap & repeat, you can easily define map, zip, zipWith, zipWith3, etc. s = zipWith ($) k = repeat mapT f xs = s (k f) xs zipWithT f as bs = s (mapT f as) bs zipT = zipWithT (,) zipWith3T f as bs cs = s (zipWithT f as bs) cs - Conal -----Original Message----- From: Mieszko Lis [mailto:elf@sandburst.com] Sent: Thursday, March 08, 2001 6:30 PM To: Eric Allen Wohlstadter Cc: haskell-cafe(a)haskell.org Subject: Re: zips and maps Eric Allen Wohlstadter wrote: > > I find myself very often needing to use this function and was wondering if > there was already a way to do this using zip,maps, and folds. Do you mind using zipWith? How about zipMap = zipWith ($) ..? -- Mieszko _______________________________________________ Haskell-Cafe mailing list Haskell-Cafe(a)haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe

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RE: zips and maps
by Conal Elliott 08 Mar '01

08 Mar '01

How about zipMap = zipWith ($) - Conal -----Original Message----- From: Eric Allen Wohlstadter [mailto:wohlstad@cs.ucdavis.edu] Sent: Thursday, March 08, 2001 6:19 PM To: haskell-cafe(a)haskell.org Subject: zips and maps I find myself very often needing to use this function and was wondering if there was already a way to do this using zip,maps, and folds. zipMap::[a->b]->[a]->[b] zipMap [] _ = [] zipMap _ [] = [] zipMap (f:fs) (x:xs) = (f x):(zipMap fs xs) Alternatively I can get the same affect like this: fstOnSnd::(a->b,a)->b fstOnSnd (f,x) = f x zipMap::[a->b]->[a]->[b] zipMap fs xs = map fstOnSnd (zip fs xs) Both require me to invent some new function (or use a lambda) which I am trying to avoid. If it is unavoidable then can someone think of a better name then zipMap? Eric Wohlstadter UCDavis Software Engineering _______________________________________________ Haskell-Cafe mailing list Haskell-Cafe(a)haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe

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Re: Summer School on Functional Programming?
by Johan Jeuring 08 Mar '01

08 Mar '01

>I was wondering if anyone knew if there was going to be a summer school on >functional programming this year. Also, where would I find information >about it? Thanks. I don't think a summer school on advanced functional programming will be organised this year. Maybe next year, but as far as I know nothing has been decided yet. I will try to start up something (which doesn't mean I will organise it!) soon. -- Johan Jeuring

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Summer School on Functional Programming?
by Eric Allen Wohlstadter 08 Mar '01

08 Mar '01

I was wondering if anyone knew if there was going to be a summer school on functional programming this year. Also, where would I find information about it? Thanks. Eric Wohlstadter UCDavis Software Engineering

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Literate Programming in Haskell?
by Tom Moertel 02 Mar '01

02 Mar '01

In the Haskell community is there a generally accepted best way to approach Literate Programming? The language has support for literate comments, but it seems that many common LP tools don't respect it. For example, in order to convert some .lhs code into LaTeX via the noweb LP tools, I had to write a preprocessor to convert the ">" code blocks into something that noweb would respect. (The preprocessor actually does a bit more and, in conjunection with noweb, gives pretty good results for little effort. For an example, see: http://www.ellium.com/~thor/hangman/cheating-hangman.lhs http://www.ellium.com/~thor/hangman/cheating-hangman.pdf ) Yet somehow, I don't think that my homebrew approach is optimal. Can anybody recommend a particularly elegant LP setup for Haskell programming? Or if you have an approach that works well for you, would you mind sharing it? Cheers, Tom

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RE: Literate Programming in Haskell?
by Conal Elliott 01 Mar '01

01 Mar '01

Has anyone gotten Ralf's lhs2tex to work under Windows? I compiled it up with GHC 4.08.1 and then GHC 4.08.2, on Windows 2k pro, and it appears to fail in all of its file reads. Haven't yet isolated a small bug example to report. - Conal -----Original Message----- From: Ralf Hinze [mailto:ralf@cs.uu.nl] Sent: Thursday, March 01, 2001 5:40 AM To: Patrik Jansson Cc: haskell-cafe(a)haskell.org Subject: Re: Literate Programming in Haskell? Patrik Jansson wrote: > A tool I am using is Ralf Hinze's > > http://www.informatik.uni-bonn.de/~ralf/Literate.tar.gz > > http://www.informatik.uni-bonn.de/~ralf/Guide.ps.gz > > It transforms .lhs files (with some formatting commands in LaTeX-style > comments) to LaTeX. Development based on this idea is something I would be > willing to participate in as I already have a fair amount of Haskell > code/articles (read: my PhD thesis;-) in this format. > > Maybe Ralf can say something about his views on further development of > lhs2tex (copyright etc.) by other people (us?). [Sorry for the delay.] In principle, everyone can use and/or modify the program to adjust it to her needs. However, since I use lhs2text almost daily, I am willing to maintain the program. So if you have suggestions, proposals etc please let me know. Cheers, Ralf _______________________________________________ Haskell-Cafe mailing list Haskell-Cafe(a)haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe

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FW: Pattern guards vs. case (was, unfortunately :Re: interesting example of laziness/ghc optimisation)
by Simon Peyton-Jones 01 Mar '01

01 Mar '01

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RE: Primitive types and Prelude shenanigans
by Simon Peyton-Jones 28 Feb '01

28 Feb '01

| Why not just let | | if x then y else z | | be syntactic sugar for | | Prelude.ifThenElse x y z The burden of my original message was that a) this is reasonable, but b) it would have to become the *defined behaviour* As you say, the "defined behaviour" would have to cover guards as well, and I'm not absolutely certain what else. The way GHC is set up now, it's relatively easy to make such changes (this wasn't true before). But it takes some design work. If someone cares enough to do the design work, and actively wants the result, I'll see how hard it is to implement. Simon

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examples using built-in state monad
by Konst Sushenko 28 Feb '01

28 Feb '01

hello, in my program i used my own parameterised state transformer monad, which is well described in literature: newtype State s m a = ST (s -> m (a,s)) ghc and hugs contain built in implementation of state monad ST. is it the same thing? the documentation is not clear on that. if it is the same, is it faster? also, could someone please recommend any samples that use the built in ST monad? thanks konst

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Re: Literate Programming in Haskell?
by Bill Halchin 28 Feb '01

28 Feb '01

Hello Haskell Community, Probably somebody else has already brought this issue up already. Why can't we have some kind of integrated literate programming model where I can I can have hyperlinks in comments to documents represented in XML?? In other words, a kind of seamless literate progarmming environment in Haskell with XML, i.e. Haskell and XML are seamless?? E.g. here is a step in the right direction by writing in Literate Haskell in HTML!: http://www.numeric-quest.com/haskell/ The stuff at this URL is pretty cool, i.e. "Haskell" scripts written in HTML. I want to also see hyperlinks to XML docs in Literate Haskell comments or maybe even to Haskell code! Regards, Bill Halchin >From: "Erik Meijer" <erik(a)meijcrosoft.com> >To: "Patrik Jansson" <patrikj(a)cs.chalmers.se>, <haskell-cafe(a)haskell.org> >CC: <ralf(a)cs.uu.nl> >Subject: Re: Literate Programming in Haskell? >Date: Mon, 19 Feb 2001 22:00:47 -0800 > >You also might take a look at Maarten Fokkinga's mira.sty >http://www.cse.ogi.edu/~mbs/src/textools/ and Mark Shileds' abbrev.sty >which >was derived from that http://www.cse.ogi.edu/~mbs/src/textools/. > >Erik >----- Original Message ----- >From: "Patrik Jansson" <patrikj(a)cs.chalmers.se> >To: <haskell-cafe(a)haskell.org> >Cc: <ralf(a)cs.uu.nl> >Sent: Monday, February 19, 2001 6:07 AM >Subject: Re: Literate Programming in Haskell? > > > > On Mon, 19 Feb 2001, Bostjan Slivnik wrote: > > > > > > > I'm also very interested in this, but ideally I would want the >output >to > > > > be in some proportional font, with symbols like =>, ->, <- replaced >with > > > > arrows, etc. Also, it would be very nice to have the code >automatically > > > > column aligned (using heuristics). > > > > > > So am I. Is anybody willing to cooperate on the desing of such tool? > > > > A tool I am using is Ralf Hinze's lhs2tex > > > > http://www.informatik.uni-bonn.de/~ralf/Literate.tar.gz > > > > http://www.informatik.uni-bonn.de/~ralf/Guide.ps.gz > > > > It transforms .lhs files (with some formatting commands in LaTeX-style > > comments) to LaTeX. Development based on this idea is something I would >be > > willing to participate in as I already have a fair amount of Haskell > > code/articles (read: my PhD thesis;-) in this format. > > > > Maybe Ralf can say something about his views on further development of > > lhs2tex (copyright etc.) by other people (us?). > > > > /Patrik Jansson > > > > PS. I have made some small improvements to lhs2tex locally and I seem to > > remember that one or two of those were actually needed to get it to > > run with my ghc version. > > > > > > _______________________________________________ > > Haskell-Cafe mailing list > > Haskell-Cafe(a)haskell.org > > http://www.haskell.org/mailman/listinfo/haskell-cafe > > >_______________________________________________ >Haskell-Cafe mailing list >Haskell-Cafe(a)haskell.org >http://www.haskell.org/mailman/listinfo/haskell-cafe _________________________________________________________________ Get your FREE download of MSN Explorer at http://explorer.msn.com

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