- Glasgow-haskell-users

RE: overzealous defaulting?
by Simon Peyton-Jones 24 Aug '04

24 Aug '04

| I feel that it must be somewhat related to this behaviour: | | Prelude> :t show . read | show . read :: String -> String | Prelude> (show . read) " 13213 " | "13213" | Prelude> (show . read) " 0x10000 " | "65536" | Prelude> (show . read) " 10000.0 " | "*** Exception: Prelude.read: no parse | | For some reason GHC defaults to Integer, even when monomorphism | restriction doesn't come into play. This is all quite reasonable. The defaulting rule says precisely what should happen. When there is an ambiguous constraint, (Show a, Read a) in this case, the defaulting rules say to try Integer and then Int (unless you have a default declaration). In this case Integer works. | Hugs chooses this funny, but IMHO more correct, type: | | Prelude> :t show . read | show . read :: (Read a, Show a) => [Char] -> [Char] It's no more correct, because it's ambiguous. Every call to (show . read) will give rise to an ambiguous constraint, which will be resolved in the same way. GHC just does it a little earlier. Simon

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profiling in 6.2.2-pre
by Serge D. Mechveliani 24 Aug '04

24 Aug '04

Please, could you help me to arrange profiling with cvs ghc-6-2-2 ? Without profiling, the Makefile contains ------------------------------------------------------------- HCFlags = $(language) -i$(idirs) -odir $(e) -hidir $(e) \ -ddump-hi-diffs \ +RTS $(space) -RTS $(extraHCOpts) extraHCOpts = pack = Package {name = "\"dm\"", \ import_dirs = ["\"$(e)\""], \ source_dirs = [], \ library_dirs = ["\"$(e)\""], \ hs_libraries = ["\"HSdm\""], \ extra_libraries = [], \ include_dirs = [], \ c_includes = [], \ package_deps = [\"data\"], \ extra_ghc_opts = [$(extraPackageOpts)], \ extra_cc_opts = [], \ extra_ld_opts = [] } obj: if [ ! -d $(e) ]; then mkdir $(e); fi $(ghc) $(HCFlags) --make DExport -package-name dm dm: obj rm -f $(e)/libHSdm.a $(e)/HSdm.o ar -qc $(e)/libHSdm.a $(wildcard $(e)/*.o) $(RANLIB) $(e)/libHSdm.a $(RANLIB) $(e)/libHSdm.a echo $(pack) | $(ghcpkg) -f $(s)/dm.conf -u -g $(ghcpkg) -f $(s)/dm.conf -l ----------------------------------------------------------------- First, I do not recall why the line $(RANLIB) $(e)/libHSdm.a repeats, by intention or by a typo. Then, for the profiling, I set extraHCOpts = -prof -hisuf p_hi -osuf p_o ... dm: obj rm -f $(e)/libHSdm* $(e)/HSdm* ar -qc $(e)/libHSdm_p.a $(wildcard $(e)/*.p_o) ~~~~ ~~~~ $(RANLIB) $(e)/libHSdm_p.a ~~~~ $(RANLIB) $(e)/libHSdm_p.a echo $(pack) | $(ghcpkg) -f $(s)/dm.conf -u -g ~~~ $(ghcpkg) -f $(s)/dm.conf -l To build the test, I command cd demotest ghc $pcpdm -prof -hisuf p_hi -osuf p_o --make Main Please, where to set foo_p.a or foo.p_a ... ? (or what it might be). And how the above $(ghcpkg) ... -u -g correlates with this. What to change in pack = Package {... ? } I set it one way, and the library build reports cannot find `libHSdm.a' on library path. I set it other way, and ghc $pcpdm -prof -hisuf p_hi -osuf p_o --make Main reports cannot find HSdm_p Should it be export/HSdm_p.o or HSdm.p_o or HSdm.o or ? export/libHSdm_p.a or libHSdm.p_a or libHSdm.a or ? As Simon Marlow has the source d.zip, maybe he could send me the corresponding settled Makefile? > In the future, Cabal will make this easier. > Have you tried using Cabal for docon yet? > It should simplify a lot of things for you. I applied profiling with GHC 2-3 years ago. It helped. And do not recall of Cabal, nor even of -hisuf p_hi -osuf p_o options. Why should GHC complicate the usage? Thank you in advance for the help, ----------------- Serge Mechveliani mechvel(a)botik.ru

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RE: overzealous defaulting?
by Simon Peyton-Jones 23 Aug '04

23 Aug '04

The binding let t = printQ falls under the monomorphism restriction. The Haskell Report would not default (Show a), so you might think you'd get an "ambiguous type variable" error. But it's so annoying to get this error for ghci> show [] that GHCi is a bit more eager about defaulting ambiguous types: it'll apply defaulting if all the constrained classes are standard, and at least one of them is numeric *or* is Show, Eq or Ord. The *or* part is the non-standard bit. Admittedly, I'm not sure this is documented. Simon | -----Original Message----- | From: glasgow-haskell-users-bounces(a)haskell.org [mailto:glasgow-haskell-users- | bounces(a)haskell.org] On Behalf Of Abraham Egnor | Sent: 23 August 2004 16:02 | To: glasgow-haskell-users(a)haskell.org | Subject: overzealous defaulting? | | I'm not sure if this is an actual bug, as opposed to an odd instance | of defaulting: | | *GUI.Parser> let printQ q = runQ q >>= print | *GUI.Parser> :t printQ | printQ :: forall a. (Show a) => Q a -> IO () | *GUI.Parser> let p = printQ | *GUI.Parser> :t p | p :: Q Integer -> IO () | | ...but I'm not sure when that would ever be the correct behavior. | | Abe | _______________________________________________ | Glasgow-haskell-users mailing list | Glasgow-haskell-users(a)haskell.org | http://www.haskell.org/mailman/listinfo/glasgow-haskell-users

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overzealous defaulting?
by Abraham Egnor 23 Aug '04

23 Aug '04

I'm not sure if this is an actual bug, as opposed to an odd instance of defaulting: *GUI.Parser> let printQ q = runQ q >>= print *GUI.Parser> :t printQ printQ :: forall a. (Show a) => Q a -> IO () *GUI.Parser> let p = printQ *GUI.Parser> :t p p :: Q Integer -> IO () ...but I'm not sure when that would ever be the correct behavior. Abe

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RE: profiling for 6.2.2
by Simon Marlow 23 Aug '04

23 Aug '04

On 21 August 2004 11:59, Serge D. Mechveliani wrote: > Dear GHC developers, > > I recall that there is also desirable to have in the official > ghc-6.2.2 > a reliable pro-filing > (for the time cost centers, for -O). Do you have outstanding bug reports for profiling in 6.2.1? I'm not aware of any, apart from one report that possibly retainer profiling has some problems, which I plan to look into. If you know of any specific issues, please let us know. Profiling is quite a large subsystem, and just saying "it's not reliable" doesn't give us much to go on. Cheers, Simon

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profiling for 6.2.2
by Serge D. Mechveliani 21 Aug '04

21 Aug '04

Dear GHC developers, I recall that there is also desirable to have in the official ghc-6.2.2 a reliable pro-filing (for the time cost centers, for -O). Although I do not test it right now, and skipping it would not cause a tragedy for me, it still will be nice if you arrange this in ghc-6.2.2. With kind regards, ----------------- Serge Mechveliani mechvel(a)botik.ru

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RE: cvsweb back up
by Simon Marlow 20 Aug '04

20 Aug '04

On 20 August 2004 14:08, Gracjan Polak wrote: > > On 20 August 2004 12:04, Gracjan Polak wrote: > > > > > >>Is there any haddoc documentation for GHC (compiler part, not > >>libraries)? I still have trouble finding my way through the > source... > > > > > Sorry, no. You could probably run Haddock on the source, although > we've > never tried and there isn't any actual documentation. > > I did want to do this myself, but I did not manage to compile haddoc > under Windows :(. > > Is there anybody having pre-build haddoc for windows? Or guide how to > do this myself? The 0.6 release wasn't particularly easy to build/use on Windows, but improvements have been made since then. The next release will be better. Cheers, Simon

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RE: getDirectoryContents fails under Windows
by Simon Marlow 20 Aug '04

20 Aug '04

On 07 August 2004 12:20, Krasimir Angelov wrote: > The getDirectoryContents function from CVS sources > fails under Windows. It seems like in the > __hscore_end_of_dir function from HsBase.h should > return 0 under Windows and ENOENT under other > platforms. Could you elaborate? getDirectoryContents appears to work fine on my HEAD build, and __hscore_end_of_dir does indeed work as you suggest. Cheers, Simon

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RE: prebuilt Haddock for Windows
by Bayley, Alistair 20 Aug '04

20 Aug '04

I have one, although I'm not sure how best to get it to you. I don't have a website, but if you point me to an ftp site I could upload it. Or I could try emailing you a zip file... It's not hard to build, but I did it with Cygwin installed - I don't know if you have this. > -----Original Message----- > From: Gracjan Polak [mailto:gracjan@student.uci.agh.edu.pl] > Sent: 20 August 2004 14:08 > To: Simon Marlow > Cc: glasgow-haskell-users(a)haskell.org > Subject: Re: cvsweb back up > > > > Simon Marlow wrote: > > > On 20 August 2004 12:04, Gracjan Polak wrote: > > > > > >>Is there any haddoc documentation for GHC (compiler part, > not >>libraries)? I still have trouble finding my way > through the source... > > > > > > Sorry, no. You could probably run Haddock on the source, > although we've > never tried and there isn't any actual > documentation. > > I did want to do this myself, but I did not manage to compile > haddoc under Windows :(. > > Is there anybody having pre-build haddoc for windows? Or > guide how to do this myself? > > > There's the > > commentary which may help: > > > > http://www.cse.unsw.edu.au/~chak/haskell/ghc/comm/ > > > > Thanks, I'm going to read it :) > > > Cheers, > > Simon ----------------------------------------- ***************************************************************** Confidentiality Note: The information contained in this message, and any attachments, may contain confidential and/or privileged material. It is intended solely for the person(s) or entity to which it is addressed. Any review, retransmission, dissemination, or taking of any action in reliance upon this information by persons or entities other than the intended recipient(s) is prohibited. If you received this in error, please contact the sender and delete the material from any computer. *****************************************************************

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cvsweb back up
by Simon Marlow 20 Aug '04

20 Aug '04

Thanks to Jeff Lewis, we now have cvsweb back up again. Browse on over to http://cvs.haskell.org/cgi-bin/cvsweb.cgi/fptools/ and enjoy! Cheers, Simon

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