- Glasgow-haskell-users

GHC rewrite rules pragma
by Jan Jakubuv 30 May '08

30 May '08

Hi, I'm trying to find out how the GHC rewrite rules pragma work, but I'm not able to make it working. I have this simple example, where I would like to specialize the function gen to spec on strings: {-# OPTIONS -O2 -fglasgow-exts #-} gen :: [a] -> a gen = head {-# RULES "gen/Char" gen=spec #-} spec :: [Char] -> Char spec x = 'x' main :: IO () main = putStr (gen "aaa":"\n") -- EOF I compile it as: ghc -O2 -fglasgow-exts spec.hs but as a result, is always prints 'a' while I expect 'x'. Is it right? What is the problem here? I would be glad for any answer. I'm using GHC 6.8.2. Sincerely, Jan.

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Re: darcs-2 executable for PowerPC Macintosh
by Christian Maeder 30 May '08

30 May '08

I was able to statically link in libgmp.a by changing my installation: 1. I've copied libgmp.a into <prefix>/lib/ghc-6.8.2 2. I've changed <prefix>/lib/ghc-6.8.2/package.conf manually: changed: ], frameworkDirs = [], frameworks = ["GMP"], to: ,"-lgmp"], frameworkDirs = [], frameworks = [], so that "-lgmp" is in ldOptions and frameworks are empty 3. called ghc with the additional flags: -optl-Xlinker -optl-search_paths_first HTH Christian zooko wrote: > Here is a darcs-2 executable for PowerPC Mac. It was built on Mac OS > 10.4, and this tarball includes the "GMP.framework", which > (unfortunately) you have to copy into /Library/Frameworks or ~/ > Library/Frameworks before darcs will run. > > If any Haskell experts can tell me how to statically link or remove > this dependency on this GMP.framework I would like to know, and then > I can build a darcs binary which doesn't require such a step during > installation. > > https://zooko.com/darcs-2-mac-powerpc.tar.bz2 > > Regards, > > Zooko

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SCC "ab cd"
by Serge D. Mechveliani 29 May '08

29 May '08

Dear GHC developers, ghc-6.8.2 compiles {-# SCC "ab cd" #-} as all right. And the GHC candidate of May 27, 2008 reports the error: "spaces are not allowed in SCC". Do you think that this latter has more sense? Is not this a matter of the programmer to give string names to SCC points? Regards, ----------------- Serge Mechveliani mechvel(a)botik.ru

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large binary footprint ?
by HP Wei 28 May '08

28 May '08

machine: Sun Sparc, with SunOS 5.10 ghc version --- 6.8.2 [ solaris-binaries downloaded from ghc site ] The Question: I compiled the code: putStr "Hello World!\n" ghc -o hello -L../lib hello.hs where ../lib contains the libgmp.so The resulting binary code size is 3.9 Mbytes I had the impression that it should be of the order of 500 Kbytes. How can I reach that number ? Thanks HP

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static linking
by Peter Gammie 28 May '08

28 May '08

Hello, I am having a bit of trouble static linking my program using GHC 6.8.2. In brief: "rt" uses "pthread", but -lrt is the final thing on the command line passed to the linker, and so the pthread symbols are not resolved. Manually moving -lpthread to the end of the collect2 command line does the trick. The question is how to do this using ghc. This is on Debian, using the 6.8.2-5 from unstable. I can provide the command lines if that is helpful. Note the same setup worked fine under GHC 6.6.1. cheers peter

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Re: GHC rewrite rules pragma
by Don Stewart 27 May '08

27 May '08

jakubuv: > Thanks lot, it works now. Now, I have just a simple question: > > Is there any chance to make rewriting working in ghci ? I think you can actually enable them by putting: {-# OPTIONS -frewrite-rules #-} at the top of the file to be interpreted. Works for me, anyway. -- Don

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ghci Problem
by Dominic Steinitz 26 May '08

26 May '08

I've built ghc and installed it but when I run ghci e.g. the up arrow keys don't work :-( Can someone let me know what I've done wrong and how to fix it? Thanks, Dominic. > dom@lagrange:~/ndp> ghci > GHCi, version 6.9.20080517: http://www.haskell.org/ghc/ :? for help > Loading package ghc-prim ... linking ... done. > Loading package integer ... linking ... done. > Loading package base ... linking ... done. > Prelude> ^[[A

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integer size on NetBSD amd64
by Donn Cave 23 May '08

23 May '08

I have been trying to get ghc working on the NetBSD AMD64 platform, and there seems to be a little problem with the integer size. With minInt and maxInt defined as they are in GHC/Base.lhs, ghc can't compile this file - it cranks away and just gets bigger until all the memory is gone. Base.lhs compiles right away if I reduce the size of minInt and maxInt by several bits - minInt = I# (-0x2000000000000000#) maxInt = I# 0x1FFFFFFFFFFFFFFF# -- minInt = I# (-0x8000000000000000#) -- maxInt = I# 0x7FFFFFFFFFFFFFFF# (... and it goes on to crash in GHC/Num.lhs.) So ... maybe somewhere in there, something isn't configured right for 64 bit integer arithmetic, even though the word size parameters in ghcautoconf.h look right? Anyone have an idea what to look for? The GHC version is 6.6.1. The .hc donor host is OpenBSD, gcc3 (NetBSD has gcc4.) The include files from NetBSD (DerivedConstants.h, GHCConstants.h, ghcautoconf.h) look fine, I just went back to the OpenBSD build to verify that they weren't changed during the build. The procedure I'm following is `Cross-compiling to produce an unregisterised GHC' http://hackage.haskell.org/trac/ghc/wiki/Building/Porting thanks! Donn Cave, donn(a)avvanta.com

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Re[4]: [Haskell-cafe] Announce: ghc-core, command line pager for reading GHC Core
by Bulat Ziganshin 23 May '08

23 May '08

Hello Duncan, Friday, May 23, 2008, 11:55:57 PM, you wrote: >> > me too. btw, this already present in jhc. inlining doesn't work in any >> > complex case since recursive functions can't be inlined >> >> GHC inlines recursive functions, too, otherwise it could not turn 'foldl' >> and friends into plain machine loops. > As I understand it, if foldl was written in the standard directly way > then ghc would not inline it well, i'm not a True GHC Hacker ;) but i was bitten by this problem in 6.4. i had a lot of SPECIALIZE pragmas in Streams library exactly because INLINE doesn't help. actually, it even does things worser by disabling some other form of optimization, i don't remember which one i have proposal of inlining even recursive functions just for one level of recursion in order to allow to call here specialized version of function. what GHC HQ will say? -- Best regards, Bulat mailto:Bulat.Ziganshin@gmail.com

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Type checker loops with innocent looking associated type synonym
by Stefan Holdermans 22 May '08

22 May '08

I've written this cute ;-) piece of code involving an associated type synonym, {-# OPTIONS_GHC -fglasgow-exts #-} class ZipWithA a where type Elem a :: * zipWithA :: [Elem a] -> a instance ZipWithA [a] where type Elem [a] = a zipWithA xs = xs instance ZipWithA b => ZipWithA ([a] -> b) where type Elem ([a] -> b) = a -> Elem b zipWithA fs = zipWithA . zipWith ($) fs and it behaves as intended: *Main> zipWithA [2, 3] :: [Int] [2,3] *Main> zipWithA [pred, succ] [2, 3] :: [Int] [1,4] *Main> zipWithA [(+), (-)] [2, 3] [5, 7] :: [Int] [7,-4] However, as soon as the overloading cannot be resolved, the type checker loops: *Main> zipWithA [head, last] ["more than", "haskell"] :: String "ml" *Main> zipWithA [head, last] ["more than", "haskell"] <<loops>> Just to be clear, I do not expect GHC to be able to type this last example, I would just have thought it would want to tell me in finite time that it cannot resolve the overloading here. Should I report this a bug? Or is it perhaps already been taken care of in the head? Or am I just plain unreasonable here? :-) Cheers, Stefan

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