- Glasgow-haskell-users

RE: Re[2]: [Haskell-cafe] ghc 6.4 import problem
by Simon Marlow 02 Jun '05

02 Jun '05

On 01 June 2005 07:24, Bulat Ziganshin wrote: > Hello Fergus, > > Tuesday, May 31, 2005, 10:24:41 PM, you wrote: > >>> import Data.Set hiding (map) >>> import qualified Data.Set as Set >>> >>> will do fine. > >> That code only compiles with ghc 6.4, and won't compile with ghc 6.2: >> you'll get an error for the "hiding (map)" part, because in 6.2 >> Data.Set does not contain a "map" function. > > btw, question to Simon Marlow and Simon PJ - how about disabling this > error message? You mean allowing import M hiding (x) even if x is not exported by M? Or making it a warning? That's certainly possible, but it constitutes an extension to Haskell 98, so it would at least require the -fglasgow-exts flag. I think you're better off keeping your code portable. Cheers, Simon

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RE: .depend in base package
by Simon Marlow 02 Jun '05

02 Jun '05

On 02 June 2005 08:22, Krasimir Angelov wrote: > I just tried to update and build my CVS tree, but the compilation > failed for base package. In the 'make boot' the .depend file is > created but it contains only the C part. The compiler is invoked as > normal and there isn't any error. The compilation is failing latter > when it tries to build Control.Arrow before Prelude. Do you have any > idea what is going wrong? It was working when I tried it last time. Fixed now, sorry about that. Cheers, Simon

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RE: make html
by Simon Marlow 02 Jun '05

02 Jun '05

On 01 June 2005 12:51, Serge D. Mechveliani wrote: > The problem was that I could not find these .gz archives by > following the www references. I wonder what I was missing. > Now, as I read your letter, I go to .../docs/latest/ and observe > them. The printable documentation is linked from the documentation page: http://www.haskell.org/ghc/documentation.html. Cheers, Simon

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RE: Simplifier output explanation needed
by Simon Marlow 02 Jun '05

02 Jun '05

On 01 June 2005 13:54, Jens Fisseler wrote: > I'm currently trying to optimize some code, in particular trying to > make some functions as strict as possible. To do this, I quite often > look for strictness annotations either in the interface files or the > the simplifier output. Doing this, something odd occured to me: > inserting a '$!' into a function call, trying to enforce eager > evaluation, the simplifier output changed. Ok, I should expect this, > but I don't understand the change. The function name got '$s' as a > prefix and the strictness annotation ('Str: DmdType SSL') vanished. > > So my question is what all those different prefixes mean. I've > stumbled across at least '$s' and '$w' (worker wrapper?). Why did the > strictness annotation disappear? Is there any documentation that can > enlighten me? $s means "specialised" I believe (Simon PJ is away until next week, so you'll have to wait until then for a definitive answer). Cheers, Simon

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.depend in base package
by Krasimir Angelov 02 Jun '05

02 Jun '05

Hello, Guys I just tried to update and build my CVS tree, but the compilation failed for base package. In the 'make boot' the .depend file is created but it contains only the C part. The compiler is invoked as normal and there isn't any error. The compilation is failing latter when it tries to build Control.Arrow before Prelude. Do you have any idea what is going wrong? It was working when I tried it last time. Cheers, Krasimir # DO NOT DELETE: Beginning of C dependencies System/CPUTime_hsc.o System/CPUTime_hsc.p_o: System/CPUTime_hsc.c System/Time_hsc.o System/Time_hsc.p_o: System/Time_hsc.c Text/Regex/Posix_hsc.o Text/Regex/Posix_hsc.p_o: Text/Regex/Posix_hsc.c # DO NOT DELETE: End of C dependencies # DO NOT DELETE: Beginning of Haskell dependencies # DO NOT DELETE: End of Haskell dependencies

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make html
by Serge D. Mechveliani 01 Jun '05

01 Jun '05

Dear GHC supporters, I have made ghc-6.4 from source by binary itself (Linux, Debian 3.1): cd ghc/6.4/ghc-6.4/ ./configure --prefix=foo make make install But it is so hard to obtain documentation! I tried make html (in the same directory). It reports ------------------------------------------------------------------------ ===fptools== Recursively making `html' in glafp-utils ghc libraries hslibs docs ... PWD = /home/mechvel/ghc/6.4/ghc-6.4 -- ... ... rm -f -rf users_guide/ stringparam base.dir users_guide/ \ --stringparam use.id.as.filename 1 \ --stringparam html.stylesheet fptools.css \ --stringparam toc.section.depth 3 --stringparam section.autolabel 1 --stringparam section.label.includes.component.label 1 \ /html/chunk.xsl users_guide.xml make[3]: stringparam: Command not found ... ************************************************************ The user has managed to make GHC: a big deal. And now has problems with making docs. This looks strange. Why not provide, say, a couple of ready .ps files for user guide and library guide? And if it is .html, let them be ready .html files. ? With kind regards, ----------------- Serge Mechveliani mechvel(a)botik.ru

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Simplifier output explanation needed
by Jens Fisseler 01 Jun '05

01 Jun '05

Hi everbody! I'm currently trying to optimize some code, in particular trying to make some functions as strict as possible. To do this, I quite often look for strictness annotations either in the interface files or the the simplifier output. Doing this, something odd occured to me: inserting a '$!' into a function call, trying to enforce eager evaluation, the simplifier output changed. Ok, I should expect this, but I don't understand the change. The function name got '$s' as a prefix and the strictness annotation ('Str: DmdType SSL') vanished. So my question is what all those different prefixes mean. I've stumbled across at least '$s' and '$w' (worker wrapper?). Why did the strictness annotation disappear? Is there any documentation that can enlighten me? Regards, Jens

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Re[2]: [Haskell-cafe] ghc 6.4 import problem
by Bulat Ziganshin 01 Jun '05

01 Jun '05

Hello Fergus, Tuesday, May 31, 2005, 10:24:41 PM, you wrote: >> import Data.Set hiding (map) >> import qualified Data.Set as Set >> >> will do fine. FH> That code only compiles with ghc 6.4, and won't compile with ghc 6.2: FH> you'll get an error for the "hiding (map)" part, because in 6.2 FH> Data.Set does not contain a "map" function. btw, question to Simon Marlow and Simon PJ - how about disabling this error message? -- Best regards, Bulat mailto:bulatz@HotPOP.com

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GHC hang
by John Goerzen 31 May '05

31 May '05

Hi, I'm trying to compile WashNGo 2.3.1 on my amd64 machine running GHC 6.4. When compiling HTMLMonad98.hs, ghc hangs. It's been running over 5 minutes now with no output or other activity. What can I do to help the GHC folks debug this?

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RE: Are new sequences really O(1)?
by Simon Marlow 31 May '05

31 May '05

On 27 May 2005 21:02, Marcin 'Qrczak' Kowalczyk wrote: > [moved from libraries to glasgow-haskell-users] > > Ross Paterson <ross(a)soi.city.ac.uk> writes: > >> GCs that happen during this process will be more expensive, as they >> have to scan the stack. I suspect that GC costs are swamping >> everything else for large n. > > I just tweaked the implementation GC in my compiler of my language, > so that minor collection doesn't scan the whole stack, but only the > part up to the deepest point where the stack pointer has been since > the previous collection. Deeper regions contain only old pointers > so they don't need to be scanned (I have only two generations). > > A program which builds a list of length 270,000 non-tail-recursively, > which in a strict language leads to proportional usage of the stack, > and performs on average 4kB of temporary allocations for each element, > so there are 9,000 GCs in total with the young heap of 128 kB, runs 10 > times faster after the change. GC takes 5% of the time instead of 88%. Nice trick. Unfortunately the same assumptions don't hold for GHC's garbage collector - objects are aged in the youngest generation, so it is usually at least two GCs before an object is promoted. We could still do the same trick, but instead we'd have to find maximum stack depth at which all objects below are in an older generation. Incedentally, how do you mark the stack depth? Overwrite a return address with a special one, and keep the real one around in a known place? Cheers, Simon

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