December 2000 - Haskell

RE: Learning Haskell and FP
by Doug Ransom 29 Dec '00

29 Dec '00

Who are the audience for the books on Advanced Functional Programming? Academics with a theoretical CS background or someone with just a bit of understanding of FP? Ideally, I would like a course suited for someone who has completed a basic FP course. > -----Original Message----- > From: Johan Jeuring [mailto:johanj@cs.uu.nl] > Sent: Thursday, December 28, 2000 6:06 AM > To: Doug Ransom > Cc: haskell(a)haskell.org > Subject: Re: Learning Haskell and FP > > > >Is there a good textbook on Functional Programming which > starts from a base > >point similar to "The craft of Functional Programming" but > more advanced in > >terms of introducing necessary topics like Category theory, > catamorphisms, > >monads, etc? I would find such a book very useful, especially if it > >concentrated on lazy functional programming. > > You might want to have a look at the series of three books on Advanced > Functional > Programming, published in LNCS, as LNCS 925, 1129, and 1608. I would > probably start with 925, which introduces monads, parser & > pretty-printing > combinators, monadic catamorphisms, constructor classes, etc. > > -- Johan Jeuring >

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Re: Learning Haskell and FP
by Fritz K Ruehr 29 Dec '00

29 Dec '00

[ Doug Ransom wrote about wanting a more advanced and design-oriented book on FP than "The Craft of Functional Programming" by Simon Thompson. In reply, Johan Jeuring recommended the Advanced Schools books (I concur). ] Let me add a few other recommendations, plus a vision of a book (not yet written, as far as I know) which might fit Doug's needs; I'll call it "The Design Patterns Haskell Companion" (see below). The "actual book" recommendations (all documented on haskell.org) * Introduction to Functional Programming using Haskell (second edition) by Richard Bird (Prentice Hall, ISBN: 0-13-484346-0) This book is an introductory text, like CFP, but it ramps up a bit faster and addresses design issues from a more advanced perspective (IMHO). It's certainly an excellent text, and it builds to a nice medium-sized design example (the program calculator of Chapter 12). It also leans toward a different style of design and programming, influenced by BMF/Squiggol. * Algebra of Programming by Richard Bird and Oege de Moor (Prentice Hall, ISBN: 0-13-507245-X) You might think of this as an advanced sequel to IFPH above, although it focuses more on the theory behind program calculation: categories and allegories figure prominently, and it leans even further in the direction indicated above. But there is nevertheless a lot of good material here which can serve as a foundation for design work, esp. the final chapters (7-10) on algorithms topics. * Algorithms: A Functional Programming Approach by Fethi Rabhi and Guy Lapalme (Addison-Wesley, ISBN: 0-201-59604-0) This is a concise tour through the usual gamut of data structures and algorithms topics typical of a "CS 2" course, but from a functional perspective. It is addressed more to people who are already familiar with programming and with the "standard" approach to DSA issues. It works very well as a reference but includes enough discussion to reward a straight reading. * Purely Functional Data Structures by Chris Okasaki (Cambridge University Press, ISBN: 0-521-66350-4) This one is similar to AFPA above (in being a tour of DSA topics from a functional perspective), but is a bit more advanced: e.g., Ch. 3 covers leftist heaps, binomial heaps and red-black trees. It also addresses issues of analysis in the context of lazy evaluation more thoroughly (Banker's method, etc.). The examples are written using SML, but an appendix (and a website) give Haskell versions. Of course, none of these books really answers the needs of the mature programmer/blossoming functional programmer who seeks advice on broader design issues in the context of lazy FP, esp. Haskell. This gap leads me to propose the fanciful book mentioned above: * The Design Patterns Haskell Companion by [someone(s) reading this list?] The title may be pandering a bit, but if the Smalltalk people can do it, why can't we? :) . In fact, the title is based on "The Design Patterns Smalltalk Companion" by Alpert, Brown and Woolf, a book I came across while reading up on design patterns. (It was recommended by a customer review on Amazon as being better than the original "gang of four" book.) The "Smalltalk Companion" serves an audience of mature programmers and attempts to document a number of "standard" design patterns in the specific context of Smalltalk. I'm not sure that the Haskell community would be comfortable referring to its collective design folklore in these terms, but I'm sure we would all welcome a good book written at this level which systematically addressed the motivation, rationale, trade-offs, etc. of the more advanced techniques of FP (i.e., monads, type and constructor classes, Xa-morphisms (for various X), higher-order and nested datatypes, etc.). As Johan mentioned, the "Advanced School" books serve this purpose to an extent, but they differ from my vision in two respects: first, they are collections of chapters on particular topics, written by different authors, and thus don't form a consistent, systematic review. Second, they are not (all) written from the specific perspective of design, so that for example they don't provide as much comparison and contrast *between* techniques. Of course, another motivation for such a book is that it might lend an air of credibility and maturity to the language, thus helping to promote it in the larger world. Casting it in terms of "design patterns" would certainly make sense for these purposes (and probably guarantees a certain audience, too), although I am still ambivalent about the need for Haskell to become a huge hit with mainstream audiences. In any case, if anyone is interested to write such a book, I will buy a copy :) . And if anyone wishes to collabrate on it, I am willing to help out. (I am not qualified to write it alone, and I think it would turn out best as a group effort in any case.) -- Fritz Ruehr fruehr(a)willamette.edu

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Re: Are anonymous type classes the right model at all? (replying to Re: Are fundeps the right model at all?)
by Julian Assange 28 Dec '00

28 Dec '00

George Russell <ger(a)tzi.de> writes: > I'm writing, but that shouldn't be too hard to tweak. In particular I have > followed SML in using "." to express qualification by something, even though > Haskell already used "." for something else, because I can't be bothered right > now to dig up a better symbol. This is why all non S-exp like lanaguage are doomed to progressive syntactic cancer as the useful parts of operator name space and syntax space become progressively polluted and mutated by one fad after another. -- Julian Assange |If you want to build a ship, don't drum up people |together to collect wood or assign them tasks proff(a)iq.org |and work, but rather teach them to long for the endless proff(a)gnu.ai.mit.edu |immensity of the sea. -- Antoine de Saint Exupery

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Haskell newsgroup
by i r thomas 28 Dec '00

28 Dec '00

How about starting a Haskell newsgroup ? The closest seems to be comp.lang.functional.

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RE: Haskell newsgroup
by Doug Ransom 28 Dec '00

28 Dec '00

That would only work if the haskell mailing list was either delete or mirrored onto a newsgroup. I would prefer a newsgroup myself for bandwidth reasons. > -----Original Message----- > From: i r thomas [mailto:israelt@optushome.com.au] > Sent: Thursday, December 28, 2000 12:53 AM > To: haskell(a)haskell.org > Subject: Haskell newsgroup > > > How about starting a Haskell newsgroup ? > The closest seems to be comp.lang.functional. > > > _______________________________________________ > Haskell mailing list > Haskell(a)haskell.org > http://www.haskell.org/mailman/listinfo/haskell >

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RE: ANNOUNCE: HaXml 1.00
by Doug Ransom 27 Dec '00

27 Dec '00

I think it is important that a good haskell XML library be included as part of the haskell runtime library given XML's relevance. > -----Original Message----- > From: Malcolm Wallace [mailto:Malcolm.Wallace@cs.york.ac.uk] > Sent: Thursday, November 16, 2000 8:42 AM > To: haskell(a)haskell.org > Subject: ANNOUNCE: HaXml 1.00 > > > We are pleased to announce > > HaXml release 1.00 > -------------------- > > HaXml is a library enabling the use of Haskell and XML together, > together with several auxiliary tools for useful XML jobs. Fuller > details are on the web page. > > > What's new since 0.9? > --------------------- > The main addition is a full treatment of the external subset for DTDs. > The DtdToHaskell tool can now slurp in a single DTD from multiple > files, and also now treats conditional sections (INCLUDE and IGNORE) > correctly. > > There is improved error-reporting: lexing and parsing errors > now report > the relevant filename, and the line/column positions are more > accurate. > > > Where do I get it? > ------------------ > Web pages: http://www.cs.york.ac.uk/fp/HaXml/ > FTP site: ftp://ftp.cs.york.ac.uk/pub/haskell/HaXml/ > > An older version of HaXml is also included in GHC's hslibs, in package > "text". This will probably be updated to 1.00 at some time. > > Regards, > Malcolm > > _______________________________________________ > Haskell mailing list > Haskell(a)haskell.org > http://www.haskell.org/mailman/listinfo/haskell >

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2nd CFP: RelMiS 2001
by Wolfram Kahl 22 Dec '00

22 Dec '00

[please post. apologies for multiple copies] SECOND CALL FOR PAPERS RelMiS 2001 - Relational Methods in Software ============================================ 7-8 April 2001, Genova, Italy http://ist.unibw-muenchen.de/RelMiS/ A Satellite Event to ETAPS 2001 Important Dates =============== Deadline for submission: 10 January 2001 Notification of acceptance: 9 February 2001 Final version due: 28 February 2001 Workshop dates: 7-8 April 2001 Workshop Topics =============== * Relational Specifications and Modelling: methods and tools, tabular methods, abstract data types * Relational Software Design and Development Techniques: relational refinement, heuristic approaches for derivation, correctness considerations, dynamic programming, greedy algorithms, catamorphisms, paramorphisms, hylomorphisms and related topics * Programming with Relations: prototyping, testing, fault tolerance, information systems, information coding * Implementing relational algebra with mixed representation of relations * Handling of Large Relations: problems of scale, innovative representations, distributed implementation Submissions =========== Submissions will be evaluated by the Program Committee for inclusion in the proceedings, which will be published in the ENTCS series. Papers must contain original contributions, be clearly written, and include appropriate reference to and comparison with related work. Papers should be submitted electronically as uuencoded PostScript files at the address relmis(a)ist.unibw-muenchen.de. Preference will be given to papers that are no shorter than 10 and no longer than 15 pages. A separate message should also be sent, with a text-only one-page abstract and with mailing addresses (both postal and electronic), telephone number and fax number of the corresponding author. Final versions will have to be submitted as LaTeX source and have to adhere to the ENTCS style! Programme Committee =================== Rudolf Berghammer (Kiel), Jules Desharnais (Quebec), Wolfram Kahl (Munich), David L. Parnas (Hamilton), Gunther Schmidt (Munich) ------------- E-Mail: relmis(a)ist.unibw-muenchen.de Workshop home page: URL: http://ist.unibw-muenchen.de/RelMiS/

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List.partition a bit too eager
by George Russell 22 Dec '00

22 Dec '00

I think the following program import List main = putStr . show . fst . (partition id) . cycle $ [True,False] should display [True,True,True,...]. But instead, for both GHC and Hugs, you get a stack overflow. Is this a bug, or could someone explain it to me?

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ANNOUNCE: Happy version 1.9
by Simon Marlow 21 Dec '00

21 Dec '00

ANNOUNCING Happy 1.9 - The LALR(1) Parser Generator for Haskell ----------------------------------------------------------------- I'm pleased to announce version 1.9 of Happy, the parser generator system for Haskell. Changes in this version, relative to version 1.8 (the previous full release): * A grammar may now contain several entry points, allowing several parsers to share parts of the grammar. * Some bugfixes. Happy is available in source form, which can be compiled with GHC version 4.xx (4.08.1 recommended), and we also provide binaries for some architectures. The Happy homepage with links to the various distributions lives at: http://www.haskell.org/happy/ Please send any bug reports and comments to simonmar(a)microsoft.com.

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GHC for Darwin?
by Ashley Yakeley 21 Dec '00

21 Dec '00

Are there any plans to port GHC to Darwin? Darwin is a FreeBSD-variant that runs on the PowerPC processor. <http://www.opensource.apple.com/projects/darwin/>. I was going to compile it myself before I remembered that compilers do platform-specific code-generation. Duh. -- Ashley Yakeley, Seattle WA

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