- Glasgow-haskell-users

RE: specializing on existentially quantified data types
by Simon Peyton-Jones 25 Nov '03

25 Nov '03

Thanks Lennart -- you are quite right. That comes of sending email before having my morning coffee. Yes you can make the specialised foo', but it'll never be called -- unless you call foo on a *particular* data structure and inlining removes the MkC wrapper etc. GHC is, of course, magical, but not quite that magical. You could do a run-time type test (via class Typeable, making Typeable a superclass of C), and then you *would* be able to call the specialised foo --- but at the cost of the test. Which is, I guess, not unreasonable. Simon | -----Original Message----- | From: Lennart Augustsson [mailto:lennart@augustsson.net] | Sent: 25 November 2003 09:08 | To: Simon Peyton-Jones | Cc: Hal Daume III; GHC Users Mailing List | Subject: Re: specializing on existentially quantified data types | | I don't know how specialised code works in ghc, so I have to ask. | Does this actually work? | The type of x is never known at the foo' call site, so the specialised | version of foo' will only be called if ghc does a run time test on the | type when invoking foo'. Does it do that? | | -- Lennart | | Simon Peyton-Jones wrote: | > | class C a where ... | > | data MkC = forall a . C a => MkC a | > | | > | foo :: MkC -> ... | > | | > | and I want to specialize foo for when the 'a' in the MkC is, say, Int. | > Is | > | this possible? | > | > Not directly. But you can say | > | > foo (MkC x) = foo' x | > | > foo' :: forall a. C a => a -> ... | > foo' x = ... | > {-# SPECIALISE foo' :: Int -> ... #-} | > | > There's no built-in mechanism I'm afraid. | > | > Simon | > | > _______________________________________________ | > Glasgow-haskell-users mailing list | > Glasgow-haskell-users(a)haskell.org | > http://www.haskell.org/mailman/listinfo/glasgow-haskell-users | > | |

2 1

RE: specializing on existentially quantified data types
by Simon Peyton-Jones 25 Nov '03

25 Nov '03

| class C a where ... | data MkC = forall a . C a => MkC a | | foo :: MkC -> ... | | and I want to specialize foo for when the 'a' in the MkC is, say, Int. Is | this possible? Not directly. But you can say foo (MkC x) = foo' x foo' :: forall a. C a => a -> ... foo' x = ... {-# SPECIALISE foo' :: Int -> ... #-} There's no built-in mechanism I'm afraid. Simon

2 1

specializing on existentially quantified data types
by Hal Daume III 25 Nov '03

25 Nov '03

Hi all, Suppose you have: class C a where ... data MkC = forall a . C a => MkC a foo :: MkC -> ... and I want to specialize foo for when the 'a' in the MkC is, say, Int. Is this possible? -- Hal Daume III | hdaume(a)isi.edu "Arrest this man, he talks in maths." | www.isi.edu/~hdaume

1 0

HTk + ghc6.01
by George Russell 24 Nov '03

24 Nov '03

Binaries for HTk (a Haskell graphics package that uses HTk) for ghc6.01 on Linux, Solaris, Windows and FreeBSD are now available from the HTk page: http://www.informatik.uni-bremen.de/htk/ Many thanks to Guy Coleman for the FreeBSD package.

1 0

List - Mutable List
by Rafael Martinez Torres 21 Nov '03

21 Nov '03

Hi: Given the classes IArray,Marray instance IArray Array.Array instance Marray IOArray e IO I'm searching for some think like MLists ( Stands for Mutable-Lists ) Is there some thing so ? I need it to implement a MQueue ... (Mutable Queue )

2 1

RE: auto cost centres for where decls
by Simon Marlow 21 Nov '03

21 Nov '03

> I have a large function with a lot of local definitions I would like > indepdent cost centres for, however, since the local definitions arn't > top-level auto-all doesn't catch them. is there some short cut to > declare a whole list of decls should have cost centres? > > I was thinking something like > > foo = ... where {-# SCC "foo" #-} > baz = ... > bar = ... > > would cause baz and bar to have cost centres named "foo.baz" and > "foo.bar" That's a good idea, but we probably won't get around to it until we do the next profiling overhaul. So that we don't lose suggestions like this, it's a good idea to add them to the feature request tracker, here: http://sourceforge.net/tracker/?group_id=8032&atid=358032 (this is the "Request a Feature" link on GHC's homepage). Cheers, Simon

1 0

auto cost centres for where decls
by John Meacham 20 Nov '03

20 Nov '03

I have a large function with a lot of local definitions I would like indepdent cost centres for, however, since the local definitions arn't top-level auto-all doesn't catch them. is there some short cut to declare a whole list of decls should have cost centres? I was thinking something like foo = ... where {-# SCC "foo" #-} baz = ... bar = ... would cause baz and bar to have cost centres named "foo.baz" and "foo.bar" John -- --------------------------------------------------------------------------- John Meacham - California Institute of Technology, Alum. - john(a)foo.net ---------------------------------------------------------------------------

1 0

RE: C--
by Simon Peyton-Jones 19 Nov '03

19 Nov '03

Norman It might be time to update the web site? Simon JP: best thing to do if you are interested in C-- is to join the mailing list. The compiler is indeed emitting code, and there is a first-cut runtime system (stack-walking etc) too. Norman and his Merrie Men have been busy. | -----Original Message----- | From: glasgow-haskell-users-bounces(a)haskell.org [mailto:glasgow-haskell-users- | bounces(a)haskell.org] On Behalf Of JP Bernardy | Sent: 19 November 2003 14:15 | To: glasgow-haskell-users(a)haskell.org | Subject: C-- | | | Hi, | | The haskell communities report says: | | "... which we want to do now that C-- is available | (http://www.cminusminus.org)" | | which is really good to hear! :) | | The most recent news on C--.org dates August 2002 | however: "the compiler is still not ready for prime | time." Any clue? | | JP. | | __________________________________ | Do you Yahoo!? | Protect your identity with Yahoo! Mail AddressGuard | http://antispam.yahoo.com/whatsnewfree | _______________________________________________ | Glasgow-haskell-users mailing list | Glasgow-haskell-users(a)haskell.org | http://www.haskell.org/mailman/listinfo/glasgow-haskell-users

2 1

C--
by JP Bernardy 19 Nov '03

19 Nov '03

Hi, The haskell communities report says: "... which we want to do now that C-- is available (http://www.cminusminus.org)" which is really good to hear! :) The most recent news on C--.org dates August 2002 however: "the compiler is still not ready for prime time." Any clue? JP. __________________________________ Do you Yahoo!? Protect your identity with Yahoo! Mail AddressGuard http://antispam.yahoo.com/whatsnewfree

1 0

Compiling ghc
by Ulf Doz 18 Nov '03

18 Nov '03

Hi list I try to compile ghc 6.0.1 on RH 9. In my compile-it-my-self-fanatism I need to do a two-stage-bootstrap. As explained in the porting and bootstrapping documentation I used the cross-port script distrbuted with the source. But in the first stage ghc issues an error message as follows: --------- ghc-6.0.1: invalid option combination Usage: For basic information, try the `--help' option. --------- The last call make did, before the error was issued: --------- ../../ghc/compiler/ghc-inplace -H16m -O -fglasgow-exts -cpp -Iinclude -#include HsBase.h -funbox-strict-fields -package-name base -keep-hc-files-too -optc-DNO_REGS -optc-DUSE_MINIINTERPRETER -fno-asm-mangling -funregisterised -fvia-C -split-objs -c GHC/Base.lhs -o GHC/Base.o -ohi GHC/Base.hi --------- I'm not familiar with ghc, more precisely, I'm completely new to Haskell. So it would be nice if someone could give me a hint. Thanks in advance... -- Robert...

2 1