January 2005 - Haskell-Cafe

Re: implementation of functional languages
by Matthew Roberts 12 Jan '05

12 Jan '05

> I am currently working my way through the tutorial book that has been > online for some time. It is perhaps the most valuable book I have and > I am really looking forward to reading this one. > > I would like to suggest we need more things like this - the Haskell > cookbook is a great initiative, but I would love books on any number > of other things. I find the conference papers are pitched just a > little too high to be educational and are often very specific. > > One example of what I mean - I had looked at Haskell parser libraries > and I know there were problems a, b and c and X was a solution to a, > etc... However, I did not "really" understand how they worked - until > I did the parser for the Core Language. Now it is all so clear! > > I am rambling a bit, but I am jut really pleased this has been made > available. > > Matt > > On 11/01/2005, at 11:32 PM, Graham Klyne wrote: > >> I think this is most welcome... I have the original printed version >> and have found it to be of great inspiration at various times. >> >> #g >> -- >> >> At 18:04 07/01/05 +0000, you wrote: >>> I'm happy to announce that my out-of-print 1987 book, >>> >>> The Implementation of Functional Programming Languages >>> >>> is now available online at >>> >>> >>> http://research.microsoft.com/%7Esimonpj/papers/slpj-book-1987/ >>> index.htm >>> >>> Very many thanks to Marnie Montgomery, who did all the work. >>> >>> Happy reading >>> >>> Simon >>> _______________________________________________ >>> Haskell-Cafe mailing list >>> Haskell-Cafe(a)haskell.org >>> http://www.haskell.org/mailman/listinfo/haskell-cafe >> >> ------------ >> Graham Klyne >> For email: >> http://www.ninebynine.org/#Contact >> >> _______________________________________________ >> Haskell-Cafe mailing list >> Haskell-Cafe(a)haskell.org >> http://www.haskell.org/mailman/listinfo/haskell-cafe > > >

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Re: [Haskell-cafe] Unit testing in Haskell
by Matthew Roberts 12 Jan '05

12 Jan '05

> > I find that I don't need unit testing frameworks. A few features of > Haskell and the associated interpreters (ghci and hugs) combine to > make "unit testing as you go" really easy. I just write a few tests > for each function I write and then some more module wide tests once > the whole module is finished. Sometimes I need a little scaffolding > to be able to output complex data types (or type synonyms), but often > just deriving Show does the job! > > To me, unit testing is two things > - testing at a low level (each and every function_ > - regression testing by running all the unit tests again > > The second may benefit more from the frameworks, but I find the first > can be done very effectively on an "ad-hoc" basis. > > Matt > > On 12/01/2005, at 6:05 AM, Dmitri Pissarenko wrote: > >> Hello! >> >> When programming in an imperative language like Java, unit tests are >> a very >> important development tool IMHO. >> >> I want to try out unit testing in Haskell and wonder what experienced >> Haskellers >> think about unit testing in Haskell in general and the hUnit testing >> framework >> (see URL below) in particular? >> >> http://hunit.sourceforge.net/ >> >> What other unit testing frameworks for Haskell do you use? >> >> TIA >> >> dap >> -- >> Dmitri Pissarenko >> Software Engineer >> http://dapissarenko.com >> _______________________________________________ >> Haskell-Cafe mailing list >> Haskell-Cafe(a)haskell.org >> http://www.haskell.org/mailman/listinfo/haskell-cafe >

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Building GUIs for Haskell programs
by Dmitri Pissarenko 12 Jan '05

12 Jan '05

Hello! I want to learn to create GUIs with Haskell. Which GUI frameworks can you recommend? Thanks Dmitri Pissarenko -- Dmitri Pissarenko Software Engineer http://dapissarenko.com

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Re: [Haskell-cafe] Building GUIs for Haskell programs
by Matthew Roberts 12 Jan '05

12 Jan '05

> Can anyone attest to the sense (or otherwise) of the following > programming "pattern" > > - program all back end stuff in Haskell and compile to library > - program all GUI stuff in *insert imperative language of choice" and > link to the library for back end functionality > > It seems the ultimate decoupling of interface from logic. > > Matt > > On 12/01/2005, at 2:33 PM, Duncan Coutts wrote: > >> On Tue, 2005-01-11 at 21:05 +0100, Dmitri Pissarenko wrote: >>> Hello! >>> >>> I want to learn to create GUIs with Haskell. >>> >>> Which GUI frameworks can you recommend? >> >> wxHaskell is good for building portable GUIs. It has an extensive >> selection of widgets and has a good API. >> >> gtk2hs is good for building GUIs that target the Linux/Gtk/Gnome >> platform (though it is portable to Windows). It is also an extensive >> toolkit. It allows you to visually design GUIs with the Glade user >> interface builder. The API style is currently more low level than that >> of wxHaskell or FLTK. >> >> There is also a binding to FLTK which is a much simpler, more light >> weight portable graphics toolkit. >> >> As far as I know, these are the only actively maintained GUI toolkits >> for Haskell at the moment. >> >> Duncan >> (gtk2hs developer) >> >> _______________________________________________ >> Haskell-Cafe mailing list >> Haskell-Cafe(a)haskell.org >> http://www.haskell.org/mailman/listinfo/haskell-cafe >

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Re: [Haskell-cafe] Hugs vs GHC (again) was: Re: Some random newbiequestions
by Dimitry Golubovsky 12 Jan '05

12 Jan '05

-------- Original Message -------- Subject: Re: [Haskell-cafe] Hugs vs GHC (again) was: Re: Some random newbiequestions Date: Mon, 10 Jan 2005 20:47:26 -0500 From: Dimitry Golubovsky <dimitry(a)golubovsky.org> To: Marcin 'Qrczak' Kowalczyk <qrczak(a)knm.org.pl> References: <3429668D0E777A499EE74A7952C382D102F30BF6(a)EUR-MSG-01.europe.corp.microsoft.com> <877jmmv2zz.fsf(a)qrnik.zagroda> <59BACBDC-6273-11D9-8389-000A95E8B0DA(a)etu.upmc.fr> <87acrgssem.fsf(a)qrnik.zagroda> Hi, Let me add a column for Hugs (summarized by looking at recent checkout from CVS, contained im several C ahd Haskell files): |Sebastien's| Marcin's | Hugs -------+-----------+----------+------ alnum | L* N* | L* N* | L*, M*, N* <1> alpha | L* | L* | L* <1> cntrl | Cc | Cc Zl Zp | c < ' ' || c >= '\DEL' && c <= '\x9f' digit | N* | Nd | c >= '0' && c <= '9' lower | Ll | Ll | Ll <1> punct | P* | P* | P* upper | Lu | Lt Lu | Lu Lt <1> blank | Z* \t\n\r | Z*(except| ' ' \t\n\r\f\v U+00A0 U+00A0 U+2007 U+202F) \t\n\v\f\r U+0085 <1>: for characters outside Latin1 range. For Latin1 characters (0 to 255), there is a lookup table defined as "unsigned char charTable[NUM_LAT1_CHARS];" I also like Ketil's idea about defining predicates like isUpper or isSpace in multiple files, quoting this: >> It's not obvious what the predicates should really mean, e.g. should >> isDigit and isHexDigit include non-ASCII digits or should isSpace >> include non-breaking space characters. > I think perhaps the answer is all of the above. The functions could > be defined in multiple modules, so that 'ASCII.isSpace' would match > the "normal" space character only, while 'Unicode.isSpace' could match > all the weird and wonderful stuff in the standard. So there might be a bunch of (perhaps autogenerated, from localedef files) modules for each locale/encoding, like ISO8859_1 or KOI_8. These modules might be imported into applications as needed. Also there would be one module autogenerated from the Unicode data files. Dimitry Golubovsky Middletown, CT

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RE: [Haskell-cafe] Information given by :info (Was: Some randomnewbie questions)
by Simon Marlow 11 Jan '05

11 Jan '05

On 10 January 2005 10:26, Sebastian Sylvan wrote: > On Mon, 10 Jan 2005 10:30:46 +0100 (MEZ), Henning Thielemann > <iakd0(a)clusterf.urz.uni-halle.de> wrote: >> What I also would like to see is the Haddock documentation >> string of a function printed by ":info" or some other command. >> > > Now _that_ would be truly useful. It's not perfect, but it's better than nothing: :def doc (\s -> let (rvar,rmod) = break (=='.') (reverse s); var = reverse rvar in System.Cmd.system ("mozilla http://www.haskell.org/ghc/docs/latest/html/libraries/base/" ++ reverse rmod ++ "html#" ++ (if (Data.Char.isUpper (head var)) then "t:" else "v:") ++ var) >> return "") eg. Prelude> :doc Prelude.head You have to use a qualified name, it only works in package base, and you can't look up data constructors. Any hackers out there want to try lifting these restrictions? Cheers, Simon

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Unit testing in Haskell
by Dmitri Pissarenko 11 Jan '05

11 Jan '05

Hello! When programming in an imperative language like Java, unit tests are a very important development tool IMHO. I want to try out unit testing in Haskell and wonder what experienced Haskellers think about unit testing in Haskell in general and the hUnit testing framework (see URL below) in particular? http://hunit.sourceforge.net/ What other unit testing frameworks for Haskell do you use? TIA dap -- Dmitri Pissarenko Software Engineer http://dapissarenko.com

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RE: [Haskell-cafe] Re: Hugs vs GHC (again) was: Re: Somerandomnewbiequestions
by Simon Marlow 11 Jan '05

11 Jan '05

On 11 January 2005 11:39, Marcin 'Qrczak' Kowalczyk wrote: > Ben Rudiak-Gould <Benjamin.Rudiak-Gould(a)cl.cam.ac.uk> writes: > >> http://www.haskell.org/~simonmar/io/System.IO.html > > "fileRead :: File -> FileOffset -> Integer -> Buffer -> IO ()" > > This is unimplementable safely if the descriptor is read concurrently > by different processes. The current position is shared. There's a big lock on File. If you want to do truly concurrent reading, you can make multiple FileInputStreams, each of which has its own file descriptor (the Unix implementation uses dup(2)). Cheers, Simon

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RE: [Haskell-cafe] Re: Hugs vs GHC (again) was: Re: Some randomnewbiequestions
by Simon Marlow 11 Jan '05

11 Jan '05

On 11 January 2005 06:52, Andre Pang wrote: > Is there a Wiki page or URL with the steram proposal? There is now: http://www.haskell.org/hawiki/HaskellStreamIO Simon

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Re: Hugs vs GHC (again)
by Dimitry Golubovsky 11 Jan '05

11 Jan '05

Ketil, Ketil Malde wrote: > Dimitry Golubovsky <golubovsky(a)gmail.com> writes: > > (Did you intend this for the list?) Yes, and I re-posted similar message on the list. > > >>>I think perhaps the answer is all of the above. The functions could >>>be defined in multiple modules, so that 'ASCII.isSpace' would match >>>the "normal" space character only, while 'Unicode.isSpace' could match >>>all the weird and wonderful stuff in the standard. >> > >>And then there might be a bunch of (perhaps autogenerated) >>locale-matching modules like ISO8859_1, KOI_8 etc. > > > Well - maybe. Another option is for these to require conversion from > to Unicode. > Right, because input of "encoding-specific" functions will be Unicode anyway. And AFAIK conversion from/to unicode may be also contained in localedef files (or for instance in Java CharToXXXX, XXXToChar classes) - I mean that there must be enough information around to build those modules automatically. Except for Unicode itself which would be autogenerated from the Unicode database files like multiple examples of doing this (including mine) that were posted on this list. Dimitry Golubovsky Middletown, CT

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