- Glasgow-haskell-users

Newbish building question
by J. Garrett Morris 13 Nov '08

13 Nov '08

Hello, I've been attempting to add some minor instrumentation to my pet copy of GHC 6.10.1. In particular, I'd like to add some code to extendInstEnv in compiler/types/InstEnv.lhs. First, I tried importing Debug.Trace into the InstEnv module, and changing the extendInstEnv function to trace "foobar". This built file, although was not tremendously useful. Next, I tried the following modification: extendInstEnv :: InstEnv -> Instance -> InstEnv extendInstEnv inst_env ins_item@(Instance { is_cls = cls_nm, is_tcs = mb_tcs }) = trace (showSDocDebug (ppr ins_item)) (addToUFM_C add inst_env cls_nm (ClsIE [ins_item] ins_tyvar)) where add (ClsIE cur_insts cur_tyvar) _ = ClsIE (ins_item : cur_insts) (ins_tyvar || cur_tyvar) ins_tyvar = not (any isJust mb_tcs) This produced the following error message: home/garrett/code/ghc-6.10.1/ghc/stage1-inplace/ghc -package-name base-4.0.0.0-hide-all-packages -no-user-package-conf -split-objs -i -idist/build -i. -idist/build/autogen -Idist/build/autogen -Idist/build -Iinclude -optP-include -optPdist/build/autogen/cabal_macros.h -#include "HsBase.h" -odir dist/build -hidir dist/build -stubdir dist/build -package ghc-prim-0.1.0.0 -package integer-0.1.0.0 -package rts-1.0 -O -package-name base -XMagicHash -XExistentialQuantification -XRank2Types -XScopedTypeVariables -XUnboxedTuples -XForeignFunctionInterface -XUnliftedFFITypes -XDeriveDataTypeable -XGeneralizedNewtypeDeriving -XFlexibleInstances -XPatternSignatures -XStandaloneDeriving -XPatternGuards -XEmptyDataDecls -XCPP -idist/build -H32m -O -O2 -Rghc-timing -XGenerics -Wall -fno-warn-deprecated-flags -c Data/Maybe.hs -o dist/build/Data/Maybe.o -ohi dist/build/Data/Maybe.hi dist/build/GHC/Base.hi Dict fun GHC.Base.$f9: Interface file inconsistency: home-package module `base:GHC.Base' is needed, but is not listed in the dependencies of the interfaces directly imported by the module being compiled Cannot continue after interface file error <<ghc: 20271680 bytes, 2 GCs, 132152/132152 avg/max bytes residency (1 samples), 31M in use, 0.01 INIT (0.02 elapsed), 0.06 MUT (0.14 elapsed), 0.03 GC (0.04 elapsed) :ghc>> I'm not sure what to do from here - showSDocDebug comes from Outputable, which was already imported by InstEnv, so it didn't seem like I should have to change anything in the build.. /g -- I am in here

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Linking error during stage2
by dermiste 13 Nov '08

13 Nov '08

Hi, I've successfully built GHC-6.10.1 from 6.6.1 on OpenBSD 4.4, and would like now to generate a hc-file-bundle to build it without pre-existing GHC. I followed the instructions in [1], but I'm stuck with this error : [....] gmake[2]: Leaving directory `/usr/ports/lang/ghc/w-ghc-6.10.1-ghc_boot/ghc-6.10.1/ghc' gmake[1]: Leaving directory `/usr/ports/lang/ghc/w-ghc-6.10.1-ghc_boot/ghc-6.10.1/compiler' gmake -C utils with-stage-2 gmake[1]: Entering directory `/usr/ports/lang/ghc/w-ghc-6.10.1-ghc_boot/ghc-6.10.1/utils' gmake -C installPackage with-stage-2 gmake[2]: Entering directory `/usr/ports/lang/ghc/w-ghc-6.10.1-ghc_boot/ghc-6.10.1/utils/installPackage' /usr/ports/lang/ghc/w-ghc-6.10.1-ghc_boot/ghc-6.10.1/libraries/cabal-bin /usr/local/bin/ghc /usr/ports/lang/ghc/w-ghc-6.10.1-ghc_boot/ghc-6.10.1/libraries/bootstrapping.conf configure --distpref dist-install \ --prefix=/NONEXISTENT --bindir=/NONEXISTENT --libdir=/NONEXISTENT --libexecdir=/NONEXISTENT --datadir=/NONEXISTENT --docdir=/NONEXISTENT --haddockdir=/NONEXISTENT --htmldir=/NONEXISTENT \ --with-compiler=/usr/ports/lang/ghc/w-ghc-6.10.1-ghc_boot/ghc-6.10.1/ghc/stage2-inplace/ghc --with-hc-pkg=/usr/ports/lang/ghc/w-ghc-6.10.1-ghc_boot/ghc-6.10.1/utils/ghc-pkg/install-inplace/bin/ghc-pkg --package-db /usr/ports/lang/ghc/w-ghc-6.10.1-ghc_boot/ghc-6.10.1/stage3.package.conf \ --libsubdir='$pkgid' --with-gcc=gcc --with-ld=/usr/bin/ld --hsc2hs-option=-I/usr/local/include --configure-option='--with-gmp-includes=/usr/local/include' --configure-option='--with-gmp-libraries=/usr/local/lib' --configure-option=--with-cc=gcc --with-hsc2hs=/usr/ports/lang/ghc/w-ghc-6.10.1-ghc_boot/ghc-6.10.1/utils/hsc2hs/install-inplace/bin/hsc2hs \ --constraint="Cabal == 1.6.0.1" Configuring installPackage-1.0... /usr/ports/lang/ghc/w-ghc-6.10.1-ghc_boot/ghc-6.10.1/libraries/cabal-bin /usr/local/bin/ghc /usr/ports/lang/ghc/w-ghc-6.10.1-ghc_boot/ghc-6.10.1/libraries/bootstrapping.conf build --distpref dist-install --ghc-option=-H32m --ghc-option=-O --ghc-option=-fvia-C --ghc-option=-Rghc-timing --ghc-option=-keep-hc-file --ghc-option=-Wall Preprocessing executables for installPackage-1.0... Building installPackage-1.0... Linking dist-install/build/installPackage/installPackage ... /usr/ports/lang/ghc/w-ghc-6.10.1-ghc_boot/ghc-6.10.1/libraries/unix/dist/build/libHSunix-2.3.1.0.a(Semaphore.o)(.text+0xac): In function `unixzm2zi3zi1zi0_SystemziPosixziSemaphore_zdwa_info': : undefined reference to `sem_trywait' {... five more like that ...} /usr/ports/lang/ghc/w-ghc-6.10.1-ghc_boot/ghc-6.10.1/libraries/unix/dist/build/libHSunix-2.3.1.0.a(Semaphore.o)(.text+0x17a4): In function `s29I_info': : undefined reference to `sem_unlink' collect2: ld returned 1 exit status <<ghc: 36084348 bytes, 5 GCs, 3492304/5176252 avg/max bytes residency (3 samples), 33M in use, 0.01 INIT (0.00 elapsed), 0.12 MUT (5.36 elapsed), 0.07 GC (0.21 elapsed) :ghc>> Obviously, the linker skips entirely /usr/lib/libpthread.a, as all the symbols defined in <semaphore.h> are into it. But its behaviour is slightly inconsistent, as I had no problem building the stage2 commenting SplitObjs in mk/build.mk some more data : I'm compiling this with the aforementioned GHC-6.10.1 bootstrapped from GHC-6.6.1. Clues anyone ? [1] http://hackage.haskell.org/trac/ghc/wiki/Building/Porting#PortingGHCtoanewp… -- Vincent Gross "So, the essence of XML is this: the problem it solves is not hard, and it does not solve the problem well." -- Jerome Simeon & Phil Wadler

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how is Linux GHC formed?
by Jason Dusek 12 Nov '08

12 Nov '08

How was the Linux binary for GHC created? I am looking at ways to compile Haskell binaries for Linux that work across distros. So far, I have been using `-static -optl-static` but today there was a weird hiccup with IO -- the Gentoo built binary worked fine on Gentoo but caught SIGPIPE intermittently on Ubuntu -- and so it's back to the drawing board. The GHC linux binary seems to work on all the Linii without discrimination, so I'd like to know what the procedure is for producing it, and what I can take away from that to put in my Cabal file. -- _jsn

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impredicative type checking
by Jeff Polakow 12 Nov '08

12 Nov '08

Hello, I filed the following bug report: This produces a type error: foo :: forall b. (b -> String, Int) foo = (const "hi", 0) bar :: (forall b. b -> String, Int) bar = foo But the types are equivalent. The ticket was closed with a comment that the types are not equivalent. However, I don't see how they are not equivalent (in the presence of impredicative polymorphism) since I can write derivations for both forall b. (b -> String /\ Int) |- (forall b. b -> String) /\ Int and (forall b. b -> String) /\ Int |- forall b. (b -> String /\ Int) in intuitionistic logic. The counter example given on the bug tracker is: foo :: forall b. (b -> String, Int) foo = undefined x :: (String, String) x = case foo of (f, _) -> (f 'a', f True) which fails to type check where the other type signature would allow it to check. However, with impredicative polymorphism, this should type check. Perhaps it is too much to ask the inference engine to infer the type of f above. However, in the original code sample, there is no type inference necessary; it is just necessary to check if the two types unify, which they should given the standard interpretation of forall. Am I missing something here? -Jeff --- This e-mail may contain confidential and/or privileged information. If you are not the intended recipient (or have received this e-mail in error) please notify the sender immediately and destroy this e-mail. Any unauthorized copying, disclosure or distribution of the material in this e-mail is strictly forbidden.

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How to getCh on MS Windows command line?
by Ahn, Ki Yung 12 Nov '08

12 Nov '08

What I mean by getCh is the non-buffered non-echoed version of getChar, which Hugs used to provided as an extension but not any more. Is there any way to have a non-buffered non-echoed single character input function on MS Windows command line using only the libraries in the MS Windows distribution packages of either GHC or Hugs? The reason to why this is important for me is because I am translating Graham Hutton's "Programming in Haskell" into Korean (soon to be published), which illustrates interactive programming with the example of a calculator that responds instantly for every keystroke of numbers and arithmetic operations running on text mode. It is very important to consider the readers who only have access to MS Windows systems, because Korean OS market share is completely skewed towards MS Windows for very embarrassing reasons that I do not even want to mention. And, isn't GHC developed in MSR anyway? :-) I remember that this is an old problem for both of the two most widely used Haskell implementation, Hugs and GHC. In ghc 6.8 getChar had a bit strange behavior. As far as I remember it always worked as if it were NoBuffering. Fortunately, in the recently released ghc 6.10, this has been fixed. We now actually have to set the buffering mode to NoBuffering with hSetBufferring to get the non-buffered behavior of getChar. But, it still isn't working on MS Windows. In Hugs, hSetBuffering neither works on Unix terminal nor on MS Windows command line. Surprisingly, it works in WinHugs. However, I cannot use WinHugs for my purpose because the interactive calculator example in the book also uses beep characters and ANSI codes which do not work in WinHugs. Thanks for any hacks or suggestions, -- Ahn, Ki Yung

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Re: problem with echo prompting in ghci (visible in emacs)
by Andrea Vezzosi 12 Nov '08

12 Nov '08

I get the same behaviour, and when I open ghci in xterm and press Ctrl-D it also echoes ^D before quitting, which is similar to the problem with haskell-mode which seems to don't like the echoing of ^J from ghci when one uses commands like C-u C-c C-t (which should copy the inferred type from the ghci buffer and insert it in the current file). I'm using the ghc package from archlinux testing repository, which is built with libedit 20080712_2.11.

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Making ghc utilize multiple cpus ?
by Marc Weber 09 Nov '08

09 Nov '08

Hi, haskell differs from other languages that it's easy to write parallel programs. So have there been any thoughts about making the ghc compiler compile modules in parallel utilizing multiple cpus yet? Of course you can use Makefiles for that or maybe cabal can be taught to do this. But restarting ghc multiple times wastes resources.. Sincerly Marc Weber

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What causes <<loop>>?
by Creighton Hogg 08 Nov '08

08 Nov '08

Hello, So I'm trying to debug an issue that is causing GHC to emit the <<loop>> warning. I was hoping to get more information about what exactly that tells me about the kind of problem, other than the obvious interpretation that I appear to be getting into some kind of infinite loop. What is GHC detecting when it emits that warning? Thanks, Creighton

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Re: ghc bug?
by Jeff Polakow 07 Nov '08

07 Nov '08

Hello, > You will be even more surpised to find out that: > > bar = (fst foo, snd foo) > > is considered correct. Does this hint give you any insight? > This tells me that GHC definitely has a bug, or at at best an infelicity. -Jeff --- This e-mail may contain confidential and/or privileged information. If you are not the intended recipient (or have received this e-mail in error) please notify the sender immediately and destroy this e-mail. Any unauthorized copying, disclosure or distribution of the material in this e-mail is strictly forbidden.

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ghc bug?
by Jeff Polakow 07 Nov '08

07 Nov '08

Hello, This compiles fine: foo :: forall b. (b -> String, Int) foo = (const "hi", 0) bar :: (forall b. b -> String, Int) bar = (const "hi", 0) but changing the definition of bar to: bar = foo causes a type error. -Jeff --- This e-mail may contain confidential and/or privileged information. If you are not the intended recipient (or have received this e-mail in error) please notify the sender immediately and destroy this e-mail. Any unauthorized copying, disclosure or distribution of the material in this e-mail is strictly forbidden.

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