November 2003 - Haskell-Cafe

RE: Aggressive inlining
by Simon Peyton-Jones 20 Nov '03

20 Nov '03

Sounds as if you might need Template Haskell http://research.microsoft.com/~simonpj/papers/meta-haskell/ Simon | -----Original Message----- | From: haskell-cafe-bounces(a)haskell.org [mailto:haskell-cafe-bounces@haskell.org] On Behalf Of Blue | Steel | Sent: 19 November 2003 22:43 | To: haskell-cafe(a)haskell.org | Subject: Aggressive inlining | | I'm working on a parlor trick. | | I would like to solve a 3-SAT problem at compile time, | so that the executable is super fast. | | Consider | --------------------------------------------------- | formula (x1,x2,x3) = (x1 || x2) && x3 | | tf = [True, False] | | assignments = [(x1,x2,x3)|x1<-tf,x2<-tf,x3<-tf] | | solutions = filter formula assignments | | main = do print solutions | --------------------------------------------------- | | Theoretically, a compiler could optimize this to | --------------------------------------------------- | main = do print [(True,True,True),...] | --------------------------------------------------- | | Is this actually possible in GHC? I've played with | inline pragmas and looked at -ddump-..., but I haven't | made much progress. | | Of course, the goal is to replace "formula" with a | formula that takes a 30-tuple instead of a triple and | really let GHC crank. | | Thanks for any help. | | | __________________________________ | Do you Yahoo!? | Protect your identity with Yahoo! Mail AddressGuard | http://antispam.yahoo.com/whatsnewfree | _______________________________________________ | Haskell-Cafe mailing list | Haskell-Cafe(a)haskell.org | http://www.haskell.org/mailman/listinfo/haskell-cafe

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GHC and Panther (Mac OS X 10.3)
by Thomas Davie 20 Nov '03

20 Nov '03

Hi, I've just upgraded to OS X 10.3 and have been having some problems with ghc. I'm using ghc 5.04.3 because it is compatible with hat - I'm doing a uni project on hat at the moment, so it's critical that it works. When I attempt to build hmake using ghc I get a whole load of errors like these: ghc -DUSE_READLINE=1 -L/sw/lib/ -lreadline -I/sw/include -package lang -c -o /Users/tatd100/Documents/Work/Project/Tools/hmake-3.08/targets/powerpc- Darwin7/obj/hmake/QSort.o QSort.hs slow-fast dropthrough not mangled _sAi_entry: addi r0,r22,12 cmplw cr7,r0,r23 ble- cr7,L11 lis r2,ha16(L_MainCapability$non_lazy_ptr) lwz r2,lo16(L_MainCapability$non_lazy_ptr)(r2) lwz r29,12(r2) b L12 L11: lwz r15,0(r22) lwz r16,4(r22) lwz r17,8(r22) addi r22,r22,12 lis r2,ha16(L_sAi_fast3$non_lazy_ptr) lwz r29,lo16(L_sAi_fast3$non_lazy_ptr)(r2) L12: mtctr r29 bctr .align 2 .section __TEXT,__text,regular,pure_instructions Which eventually drop down to one error that kills the whole process: ghc -DUSE_READLINE=1 -L/sw/lib/ -lreadline -I/sw/include -package lang -c -cpp -o /Users/tatd100/Documents/Work/Project/Tools/hmake-3.08/targets/powerpc- Darwin7/obj/hmake/Compat.o Compat.hs Compat.hs:1: parse error on input `#' make[1]: *** [/Users/tatd100/Documents/Work/Project/Tools/hmake-3.08/targets/ powerpc-Darwin7/obj/hmake/Compat.o] Error 1 make: *** [targets/powerpc-Darwin7/hmake-ghc] Error 2 I'm guessing that there's some binary compatibility issues here... Could it be panther using gcc3.3? Thanks Bob

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Functional Code Generation
by Brandon Michael Moore 19 Nov '03

19 Nov '03

I think I remeber seeing a paper about techniques for writing code generators in Haskell targeting stack based bytecodes that encoded bytecode sequences in a way that the typechecker could give you some sanity guarantees, and then talked a bit about using dynamic programming for optimizing bytecode sequences. I haven't turned up anything searching Google and CiteSeer (though I don't really know good words to search for), so I'm hoping someone here remembers. A friend of mine is implementing a Scheme -> OCaml bytecode compiler for a class and I think some of the ideas from that paper would help, whatever they were. Thanks Brandon

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Aggressive inlining
by Blue Steel 19 Nov '03

19 Nov '03

I'm working on a parlor trick. I would like to solve a 3-SAT problem at compile time, so that the executable is super fast. Consider --------------------------------------------------- formula (x1,x2,x3) = (x1 || x2) && x3 tf = [True, False] assignments = [(x1,x2,x3)|x1<-tf,x2<-tf,x3<-tf] solutions = filter formula assignments main = do print solutions --------------------------------------------------- Theoretically, a compiler could optimize this to --------------------------------------------------- main = do print [(True,True,True),...] --------------------------------------------------- Is this actually possible in GHC? I've played with inline pragmas and looked at -ddump-..., but I haven't made much progress. Of course, the goal is to replace "formula" with a formula that takes a 30-tuple instead of a triple and really let GHC crank. Thanks for any help. __________________________________ Do you Yahoo!? Protect your identity with Yahoo! Mail AddressGuard http://antispam.yahoo.com/whatsnewfree

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Re: Haskell Server Pages
by Niklas Broberg 19 Nov '03

19 Nov '03

I am part of a project working on an implementation of an HSP system, very much inspired by the paper you mention by Eric Meijer and Daan Leijen. It is our goal to make a complete HSP system with a model for HTML in Haskell, a pre-processor, and a runtime system/plugins for various web servers. The ETA is set to May -04, until then you can follow our progress at http://www.dtek.chalmers.se/~d00nibro/hsp/ There is a simple version of a pre-processor available from our Download page, but use it at your own risk ;) /Niklas _________________________________________________________________ MSN 8 with e-mail virus protection service: 2 months FREE* http://join.msn.com/?page=features/virus

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Partially ordered collections (revisited)
by Graham Klyne 19 Nov '03

19 Nov '03

I've taken the suggestions made by Tom and Robert and combined them into a new module with some supporting functions and test cases. A copy is attached, in case it's of use to anyone. #g ------------ Graham Klyne For email: http://www.ninebynine.org/#Contact

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Haskell Server Pages
by "Grigory Makeev 19 Nov '03

19 Nov '03

Hello, I'm interested in writing a personal home-page in a functional way, and i'm in need of some clues. Is there any resource, devoted exactly to the functional approaches to the web programming and web design? I've seen a WASH project, but i'm not really saticefied with the way pages look there. What i trully need is something like Haskell Server Pages system, from Erik Meijer's "Haskell Server Pages. Functional programming and the Battle for the Middle Tier" paper, but i haven't found any implementation of that. I'm not very good at either web programming, or Haskell, i'm just a fan of it, and there's no way i can implement that myself. Is anyone writing currently something like table = <table border="1"> <% mkRows cells%></table> Can anyone provide me with some links? Best regards, Grigory

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Haskell Server Pages
by "Grigory Makeev 19 Nov '03

19 Nov '03

Hello, I'm interested in writing a personal home-page in a functional way, and i'm in need of some clues. Is there any resource, devoted exactly to the functional approaches to the web programming and web design? I've seen a WASH project, but i'm not really saticefied with the way pages look there. What i trully need is something like Haskell Server Pages system, from Erik Meijer's "Haskell Server Pages. Functional programming and the Battle for the Middle Tier" paper, but i haven't found any implementation of that. I'm not very good at either web programming, or Haskell, i'm just a fan of it, and there's no way i can implement that myself. Is anyone writing currently something like table = <table border="1"> <% mkRows cells%></table> Can anyone provide me with some links? Best regards, Grigory

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oh, i'm sorry for doubling a message
by "Grigory Makeev 19 Nov '03

19 Nov '03

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There is flexible exception handling in Haskell?
by 7253146＠informatica.alumnos.uma.es 18 Nov '03

18 Nov '03

Hi all. I am porting to Haskell a small zlib-based library for .zip files (I have not seen any released package for it, although it should very useful). The matters come when I try to address exceptional conditions: all the library functions return a integer code with OK/SOMEERROR meaning. The most natural way to carry the exceptional situations should be raise IO exceptions, but here comes the problem: how can I define new Exception codes, instead of raising userError all the time? I think it makes sense for a library to raise specialized exceptions, instead of userErrors. There is such a mechanism? Can someone help? Thanks. --------------------------------------------- Este mensaje lo ha enviado un Alumno de la Universidad de Malaga. http://www.alumnos.uma.es/

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