September 2013 - ghc-devs

delete remote branch
by Nicolas Frisby 12 Sep '13

12 Sep '13

I just merged in my -fdicts-strict work, so I was deleting the old branch… but it's rejected for some reason. $ git push origin --delete dicts-strict remote: performing tab-check... remote: + refs/heads/dicts-strict ghc <my-username> DENIED by fallthru remote: error: hook declined to update refs/heads/dicts-strict To ssh://git@git.haskell.org/ghc.git ! [remote rejected] dicts-strict (hook declined) error: failed to push some refs to 'ssh://git@git.haskell.org/ghc.git' Git gurus chime in? Thanks.

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Profiling segfaulting in HEAD again
by Edward Z. Yang 12 Sep '13

12 Sep '13

Hey folks, I noticed that profiling has started segfaulting again in HEAD. Anyone recently push something that might be triggering this? Edward

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管理者如何才能走出管理的困惑
by 樊泽邦 11 Sep '13

11 Sep '13

1 0

RE: [core libraries] RE: Alex and new Bool primops
by Simon Peyton-Jones 11 Sep '13

11 Sep '13

(Simon M: are you ok with updating Alex? You were the one of those who argued strongly for using the old names for the new primops.) The difficulty is this. · Alex generates Haskell code, by transforming Foo.x into Foo.hs · The generated Foo.hs contains references to comparison primops, say (>#) :: Int# -> Int# -> Bool · Therefore Foo.hs will not work with GHC 7.8 if we have changed the type of (>#), which is what I think we have agreed to do. · The solution is to make Alex generates a Foo.hs that is compilable either with GHC 7.8 or 7.6, by including enough CPP directives. Alex already does this for compatibility with earlier GHCs · However, until there is a new version of Alex, you simply won’t be able to bootstrap GHC 7.8 (or indeed the current HEAD). That’s all there is to it. It’s tiresome and trivial in a sense, but it’s a choice we have to make. It might be perfectly reasonable to say · You can’t build GHC 7.8 from source with the Haskell Platform until a new HP comes out with the new Alex (which will be soon). · Unless you install the new Alex manually This seems not too bad; people who build GHC from source are generally pretty savvy. The choice between the two is what we seek your guidance on. (Incidentally, a very similar situation has arisen for Happy: see http://ghc.haskell.org/trac/ghc/ticket/8022. But there the cost of perpetuating the status quo for another release cycle seems minimal.) Simon From: michael.snoyman(a)gmail.com [mailto:michael.snoyman@gmail.com] On Behalf Of Michael Snoyman Sent: 10 September 2013 05:28 To: Simon Peyton-Jones Cc: core-libraries-committee(a)haskell.org; ghc-devs; Geoffrey Mainland; Jan Stolarek Subject: Re: [core libraries] RE: Alex and new Bool primops I'll admit a fair amount of ignorance of the GHC build process. But wouldn't it be standard that any tool used in the GHC build process itself, and built by GHC itself, would need to have some conditional compilation in place to handle API changes? It seems like the questions here are whether we should ever allow breaking changes in the API, and in this case whether the changes are coming too late in the development cycle. It seems like we've agreed on the first count that it's beneficial to allow breaking API changes. It could be that in this case we're too late in the dev cycle. In this case, it sounds like including the compatibility module in Alex would be most expedient, but I'd defer to those who understand the process better than me. On Mon, Sep 9, 2013 at 5:38 PM, Simon Peyton-Jones <simonpj(a)microsoft.com<mailto:simonpj@microsoft.com>> wrote: Dear Core Libraries Committee I think we need your advice. This thread (mostly on ghc-devs) shows that if the shim-package and boolean-primop decision goes as currently proposed, then we'll need a new release of Alex * Either to generate an import of GHC.Exts.Compat (ie depend on the shim package) * Or to make its own local tiny shim module for the primops it uses * Or maybe some other plan (Alex already has quite a bit of stuff designed to make it generate code that will be compilable with a variety of GHCs.) Moreover this new release of Alex will be necessary simply in order to allow 7.8 (or indeed 7.7) to be bootstrapped. So, for example, the current HP could not be used to build GHC. How would you like us to proceed? Thanks! Simon | -----Original Message----- | From: ghc-devs [mailto:ghc-devs-bounces@haskell.org<mailto:ghc-devs-bounces@haskell.org>] On Behalf Of | Geoffrey Mainland | Sent: 09 September 2013 16:14 | To: Jan Stolarek | Cc: ghc-devs | Subject: Re: Alex and new Bool primops | | I say this only somewhat facetiously, but this is *exactly* the sort of | problem that the pro-backwards compatibility camp anticipates, and I | mean the "pro-backwards compatibility camp" in the most general possible | way :) The point is that you can never anticipate all the ways in which | breaking backwards compatibility breaks things. How much "technical | debt" is really accrued with backwards compatible primops? What is | preventing us from doing the so-called "Right Thing" *after* the 7.8 | release? | | Anyway, the one solution I can think of off the top of my head is to | patch Alex's templates to use an #ifdef to pick primops based on the | version of GHC being used for compilation. That will need to be done | anyway. | | As an aside, I think any discussion that involves making decisions that | effect the community as a whole should have a public mail archive. | | Geoff | | On 09/09/2013 11:02 AM, Jan Stolarek wrote: | > I think the there was a general agreement in the committee that we | should follow the best long-term solution, not the best short-term one. | Here are two arguments (Plan B = break backwards compatibility): | > | > > I'd rather not hamstring GHC.* with a rats nest of backwards | compatibility decisions, | > > which all come at accreted costs, the mortgage for which is to be | paid down forever | > > by future development efforts. | > | > > I vote for plan B on the grounds that it's the Right Thing and the | > > group that it breaks is both small and savvy. | > | > > [implementing backwards compatibility solution] only works once, | though. We're in exactly the same boat on all future primop redesigns. | > | > There was also a decision of providing a backwards compatibility | package that would make it easy for library authors to create packages | that are compatible both with 7.6 and 7.8 (summarized here: | http://www.haskell.org/haskellwiki/Compatibility_Modules) Sadly, | there's no web archive for that list so I can't point you to the | discussion. | > | > Anyway, this is clearly something no one has anticipated and the | question is whether we have a good way to solve that problem? | > | > Janek | > | > ----- Oryginalna wiadomość ----- | > Od: "Geoffrey Mainland" <mainland(a)apeiron.net<mailto:mainland@apeiron.net>> | > Do: "Jan Stolarek" <jan.stolarek(a)p.lodz.pl<mailto:jan.stolarek@p.lodz.pl>> | > DW: "ghc-devs" <ghc-devs(a)haskell.org<mailto:ghc-devs@haskell.org>> | > Wysłane: poniedziałek, 9 wrzesień 2013 15:40:09 | > Temat: Re: Alex and new Bool primops | > | > Perhaps the core libraries committee should reconsider their decision? | > :) Backwards compatibility is good. If HEAD implements the backwards | > compatibility plan that Simon PJ and I suggested and said plan is | > working, there should be a compelling reason to break compatibility | and | > have to go chasing down all the follow-on breakage (in, e.g., Alex) so | > close to release. | > | > What was the committee's reasoning? | > | > Geoff | > | > On 09/09/2013 10:08 AM, Jan Stolarek wrote: | >> I am refactoring new Bool primops (#6135). There was a discussion on | core-libraries-commitee list and the decision was made that we should | keep names of primops we used so far and change their type signature | (right now HEAD has different names for new primops and reuses old names | for compatibility wrappers). I've changed names of the primops and | removed the wrappers but I can't bootstrap GHC because old primops are | hardwired into Alex. I get this build error when attempting to build | stage 2 compiler: | >> | >> compiler/stage2/build/Lexer.hs:2348:34: | >> Couldn't match expected type 'Bool' with actual type 'Int#' | >> In the first argument of '(&&)', namely '(offset >=# 0#)' | >> In the expression: (offset >=# 0#) && (check ==# ord_c) | >> In the expression: | >> if (offset >=# 0#) && (check ==# ord_c) then | >> alexIndexInt16OffAddr alex_table offset | >> else | >> alexIndexInt16OffAddr alex_deflt s | >> | >> compiler/stage2/build/Lexer.hs:2348:53: | >> Couldn't match expected type 'Bool' with actual type 'Int#' | >> In the second argument of '(&&)', namely '(check ==# ord_c)' | >> In the expression: (offset >=# 0#) && (check ==# ord_c) | >> In the expression: | >> if (offset >=# 0#) && (check ==# ord_c) then | >> alexIndexInt16OffAddr alex_table offset | >> else | >> alexIndexInt16OffAddr alex_deflt s | >> | >> And indeed, looking at Lexer.hs I see: | >> | >> alex_scan_tkn user orig_input len input s last_acc = | >> (...) -- some irrelevant code here | >> (!(new_s)) = if (offset >=# 0#) && (check ==# ord_c) | >> then alexIndexInt16OffAddr alex_table | offset | >> else alexIndexInt16OffAddr alex_deflt s | >> | >> So to compile GHC, Alex would need to generate different code for GHC | 7.6.3 and below, and different for GHC 7.7 and above (or alternatively | it could generate #if pragmas), but this means we'd need to update Alex. | I created compatibility module within GHC called ExtsCompat46 and tried | adding it to list of imported modules, but in generated Lexer.hs Alex | adds a bunch of other modules among which is GHC.Exts, which conflicts | with import of ExtsCompat46: | >> | >> compiler/stage1/build/Lexer.hs:2349:41: | >> Ambiguous occurrence `>=#' | >> It could refer to either `ExtsCompat46.>=#', | >> imported from `ExtsCompat46' at | compiler/parser/Lexer.x:79:1-19 | >> or `GHC.Exts.>=#', | >> imported from `GHC.Exts' at | compiler/stage1/build/Lexer.hs:75:1-15 | >> (and originally defined in `ghc- | prim:GHC.Prim') | >> | >> Again, we would need updated version of Alex to generate correct code | (also, this would break in the future after removing that compatibility | module). I don't see a way out of this. Help? | >> | >> Janek | >> | >> _______________________________________________ | >> ghc-devs mailing list | >> ghc-devs(a)haskell.org<mailto:ghc-devs@haskell.org> | >> http://www.haskell.org/mailman/listinfo/ghc-devs | > | | | _______________________________________________ | ghc-devs mailing list | ghc-devs(a)haskell.org<mailto:ghc-devs@haskell.org> | http://www.haskell.org/mailman/listinfo/ghc-devs -- You received this message because you are subscribed to the Google Groups "haskell-core-libraries" group. To unsubscribe from this group and stop receiving emails from it, send an email to haskell-core-libraries+unsubscribe(a)googlegroups.com<mailto:haskell-core-libraries%2Bunsubscribe@googlegroups.com>. For more options, visit https://groups.google.com/groups/opt_out.

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RE: GHC 7.8 release status
by Simon Peyton-Jones 11 Sep '13

11 Sep '13

I do need more than a patch, please, please. A wiki page explaining the design, as seen by the user (of the GHC API), the problems it solves, and the use-cases it enables, would be most helpful. Simon | -----Original Message----- | From: Thomas Schilling [mailto:nominolo@googlemail.com] | Sent: 04 September 2013 17:26 | To: Simon Peyton-Jones; Luite Stegeman | Cc: Nicolas Frisby; "Pedro Magalhães (dreixel(a)gmail.com)"; Richard | Eisenberg (eir(a)cis.upenn.edu) Geoffrey Mainland | (mainland(a)cs.drexel.edu) Iavor Diatchki; Austin Seipp; Edsko de Vries; | Ryan Newton (rrnewton(a)gmail.com) David Luposchainsky; ghc- | devs(a)haskell.org | Subject: Re: GHC 7.8 release status | | | On 4 Sep 2013, at 15:52, Simon Peyton-Jones <simonpj(a)microsoft.com> | wrote: | | > Edsko/Thomas/Luite: if you want anything for 7.8 it'll have to be | jolly soon. At the moment I don't even know the motivation or design, | let alone implementation. Could you make a wiki page explaining the | proposed design? Is it really important to do this for 7.8? | | Yes, it is quite important to get this into 7.8. Not having these | features in GHC makes it very difficult for people to adopt GHCJS. One | could argue that GHCJS is not yet production-ready anyway and users that | want to try it can figure out building GHC from source to use it, but | this doesn't quite apply. | | 1. GHCJS targets a wider audience than users brave enough to compile | GHC from source. In addition, the next chance to get these features into | GHC is in a year from now, so when GHCJS becomes more mature then this | will be a major hurdle for adoption. | | 2. These changes are also required for IDE tools which really mustn't | require users to build a custom version of GHC. | | | Luite's design is actually very flexible. It simply allows GHC API | users to provide functions that are called instead of (or in addition | to) existing functions in GHC. Instead of calling, say, "genHardCode", | the driver now looks up whether the user has specified a hook for | genHardCode and calls that instead. | | Currently we only specify a small number of hooks that are sufficient | for our use cases. Future releases of GHC can be extended to include | more hooks, if that is needed. | | Hooks are stored as an untyped map inside the DynFlags (to avoid issues | with circular dependencies). Each hook is looked up using a single- | constructor type and type families are used to make this type safe. | There is one use of unsafeCoerce to avoid having to make every hook | function an instance of Typeable. | | Unlike CorePlugins, it is only a GHC API feature, and users cannot | specify plugins to be added via command line options. If we can come up | with a good design, then we could add this in GHC 7.10, but it is not | necessary at this point. | | Luite: Do you have a link to your latest patch?

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extending GHC plugins with Hooks
by Luite Stegeman 11 Sep '13

11 Sep '13

hi all, Sorry for taking so long to get back with this. I'm proposing a somewhat general way for adding 'hooks' to the GHC API, where users can override parts of the default compiling pipeline. Hooks are simply functions or actions that replace existing compiler functionality. This means that usually only one application can use a specific hook at a time. The obvious data structure to store the hooks is DynFlags. Unfortunately defining hooks in DynFlags directly would give birth to the mother of all import cycles, and it would also break the split-dll scheme on Windows. So here's the idea: - Define each hook in the module where it's exported - For each hook make a 'phantom' DataType and an instance for the Hook type familiy - Add a TypeRep based map in DynFlags [0] - For each hooked function, check for existence of a hook in DynFlags, otherwise run the default. Example: https://github.com/ghcjs/ghcjs-build/blob/master/refs/patches/ghc-ghcjs.pat… Now this approach does have some disadvantages: - No clear integration with existing plugins (I've tried adding an onLoadPlugin field to Plugin, where the Plugin could update DynFlags when it's loaded, but it was a bit messy, and plugins would not be loaded in time for some hooks, particularly what Edsko needs) - More of GHC depends on type families - Decentralized hooks definitions feel a bit messy So I'm open to suggestions for improvements (or replacements) of this scheme. I have some time the coming weeks to clean up or change the patch. We've been testing some hooks with GHCJS for a while, and so far they seem to provide what we need (but I'm going to doublecheck the coming weeks that we don't have missing functionality): - Customizations for linking JavaScript code with our own library locations [1] - Hooking into the DriverPipeline so we can use the compilation manager [2] - Desugaring customizations to remove some C-isms from the FFI code [3] - Typechecking foreign import javascript imports [4] - Override the built-in GHC.Prim so we can customize primop types [5] I think it's easy to add those for Edsko and Thomas as well. luite [0] https://github.com/ghcjs/ghcjs-build/blob/master/refs/patches/ghc-ghcjs.pat… [1] https://github.com/ghcjs/ghcjs/blob/master/src/Compiler/GhcjsHooks.hs#L44 [2] https://github.com/ghcjs/ghcjs/blob/master/src/Compiler/GhcjsHooks.hs#L192 https://github.com/ghcjs/ghcjs-build/blob/master/refs/patches/ghc-ghcjs.pat… [3] https://github.com/ghcjs/ghcjs/blob/master/src/Gen2/Foreign.hs#L67 https://github.com/ghcjs/ghcjs-build/blob/master/refs/patches/ghc-ghcjs.pat… [4] https://github.com/ghcjs/ghcjs/blob/master/src/Gen2/Foreign.hs#L68 https://github.com/ghcjs/ghcjs-build/blob/master/refs/patches/ghc-ghcjs.pat… [5] https://github.com/ghcjs/ghcjs/blob/master/src/Compiler/GhcjsHooks.hs#L191 https://github.com/ghcjs/ghcjs-build/blob/master/refs/patches/ghc-ghcjs.pat… (sorry the linked patch also contains other modifications required for GHCJS, that i'm going to submit separately)

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Re: [core libraries] RE: Alex and new Bool primops
by Jan Stolarek 11 Sep '13

11 Sep '13

Also got email error for my last message, so I'm reposting it below with some more information. From a technical point of view changes to Alex and Happy are simple and already implemented on my branch: https://github.com/jstolarek/alex/commit/32d4244894ae2702d965415483d0479d91… https://github.com/jstolarek/happy/commit/430ebe1f82744818cc488cd45fee0effa… I say we bite the bullet - this moment is as good as any other. There is one important thing to point out. After updating Alex and Happy you will need to update HEAD and rebase your older branches on top of HEAD containing new primops. Again, this is unavoidable no matter when we decide to make the change. Given that my changes affect 7 libraries (and only one of them is a submodule) you would need to rebase anyway. Janek ----- Oryginalna wiadomość ----- Od: "Michael Snoyman" <michael(a)snoyman.com> Do: "Simon Peyton-Jones" <simonpj(a)microsoft.com> DW: core-libraries-committee(a)haskell.org, "ghc-devs" <ghc-devs(a)haskell.org>, "Geoffrey Mainland" <mainland(a)apeiron.net>, "Jan Stolarek" <jan.stolarek(a)p.lodz.pl>, "Simon Marlow" <marlowsd(a)gmail.com> Wysłane: środa, 11 wrzesień 2013 5:04:24 Temat: Re: [core libraries] RE: Alex and new Bool primops I got a mail delivery error on this, so I'm going to resend. Apologies to those who get this twice. On Tue, Sep 10, 2013 at 6:37 PM, Michael Snoyman <michael(a)snoyman.com>wrote: > Having a requirement to manually install a newer Alex doesn't seem too > onerous to me. That would be my recommendation. > > > On Tue, Sep 10, 2013 at 11:53 AM, Simon Peyton-Jones < > simonpj(a)microsoft.com> wrote: > >> (Simon M: are you ok with updating Alex? You were the one of those who >> argued strongly for using the old names for the new primops.)**** >> >> ** ** >> >> The difficulty is this. **** >> >> **· **Alex generates Haskell code, by transforming Foo.x into >> Foo.hs**** >> >> **· **The generated Foo.hs contains references to comparison >> primops, say (>#) :: Int# -> Int# -> Bool**** >> >> **· **Therefore Foo.hs will not work with GHC 7.8 if we have >> changed the type of (>#), which is what I think we have agreed to do.**** >> >> **· **The solution is to make Alex generates a Foo.hs that is >> compilable either with GHC 7.8 or 7.6, by including enough CPP directives. >> Alex already does this for compatibility with earlier GHCs**** >> >> **· **However, until there is a new version of Alex, you simply >> won’t be able to bootstrap GHC 7.8 (or indeed the current HEAD).**** >> >> ** ** >> >> That’s all there is to it. It’s tiresome and trivial in a sense, but >> it’s a choice we have to make.**** >> >> ** ** >> >> It might be perfectly reasonable to say **** >> >> **· **You can’t build GHC 7.8 from source with the Haskell >> Platform until a new HP comes out with the new Alex (which will be soon). >> **** >> >> **· **Unless you install the new Alex manually**** >> >> ** ** >> >> This seems not too bad; people who build GHC from source are generally >> pretty savvy. The choice between the two is what we seek your guidance on. >> **** >> >> ** ** >> >> (Incidentally, a very similar situation has arisen for Happy: see >> http://ghc.haskell.org/trac/ghc/ticket/8022. But there the cost of >> perpetuating the status quo for another release cycle seems minimal.)**** >> >> ** ** >> >> Simon**** >> >> ** ** >> >> *From:* michael.snoyman(a)gmail.com [mailto:michael.snoyman@gmail.com] *On >> Behalf Of *Michael Snoyman >> *Sent:* 10 September 2013 05:28 >> *To:* Simon Peyton-Jones >> *Cc:* core-libraries-committee(a)haskell.org; ghc-devs; Geoffrey Mainland; >> Jan Stolarek >> *Subject:* Re: [core libraries] RE: Alex and new Bool primops**** >> >> ** ** >> >> I'll admit a fair amount of ignorance of the GHC build process. But >> wouldn't it be standard that any tool used in the GHC build process itself, >> and built by GHC itself, would need to have some conditional compilation in >> place to handle API changes? It seems like the questions here are whether >> we should ever allow breaking changes in the API, and in this case whether >> the changes are coming too late in the development cycle. It seems like >> we've agreed on the first count that it's beneficial to allow breaking API >> changes. It could be that in this case we're too late in the dev cycle.** >> ** >> >> ** ** >> >> In this case, it sounds like including the compatibility module in Alex >> would be most expedient, but I'd defer to those who understand the process >> better than me.**** >> >> ** ** >> >> On Mon, Sep 9, 2013 at 5:38 PM, Simon Peyton-Jones <simonpj(a)microsoft.com> >> wrote:**** >> >> Dear Core Libraries Committee >> >> I think we need your advice. >> >> This thread (mostly on ghc-devs) shows that if the shim-package and >> boolean-primop decision goes as currently proposed, then we'll need a new >> release of Alex >> * Either to generate an import of GHC.Exts.Compat >> (ie depend on the shim package) >> * Or to make its own local tiny shim module for the primops it uses >> * Or maybe some other plan >> (Alex already has quite a bit of stuff designed to make it generate code >> that will be compilable with a variety of GHCs.) >> >> Moreover this new release of Alex will be necessary simply in order to >> allow 7.8 (or indeed 7.7) to be bootstrapped. So, for example, the current >> HP could not be used to build GHC. >> >> How would you like us to proceed? Thanks!**** >> >> >> Simon >> >> | -----Original Message----- >> | From: ghc-devs [mailto:ghc-devs-bounces@haskell.org] On Behalf Of >> | Geoffrey Mainland**** >> >> | Sent: 09 September 2013 16:14 >> | To: Jan Stolarek >> | Cc: ghc-devs >> | Subject: Re: Alex and new Bool primops >> |**** >> >> | I say this only somewhat facetiously, but this is *exactly* the sort of >> | problem that the pro-backwards compatibility camp anticipates, and I >> | mean the "pro-backwards compatibility camp" in the most general possible >> | way :) The point is that you can never anticipate all the ways in which >> | breaking backwards compatibility breaks things. How much "technical >> | debt" is really accrued with backwards compatible primops? What is >> | preventing us from doing the so-called "Right Thing" *after* the 7.8 >> | release? >> | >> | Anyway, the one solution I can think of off the top of my head is to >> | patch Alex's templates to use an #ifdef to pick primops based on the >> | version of GHC being used for compilation. That will need to be done >> | anyway. >> | >> | As an aside, I think any discussion that involves making decisions that >> | effect the community as a whole should have a public mail archive. >> | >> | Geoff >> | >> | On 09/09/2013 11:02 AM, Jan Stolarek wrote: >> | > I think the there was a general agreement in the committee that we >> | should follow the best long-term solution, not the best short-term one. >> | Here are two arguments (Plan B = break backwards compatibility): >> | > >> | > > I'd rather not hamstring GHC.* with a rats nest of backwards >> | compatibility decisions, >> | > > which all come at accreted costs, the mortgage for which is to be >> | paid down forever >> | > > by future development efforts. >> | > >> | > > I vote for plan B on the grounds that it's the Right Thing and the >> | > > group that it breaks is both small and savvy. >> | > >> | > > [implementing backwards compatibility solution] only works once, >> | though. We're in exactly the same boat on all future primop redesigns. >> | > >> | > There was also a decision of providing a backwards compatibility >> | package that would make it easy for library authors to create packages >> | that are compatible both with 7.6 and 7.8 (summarized here: >> | http://www.haskell.org/haskellwiki/Compatibility_Modules) Sadly, >> | there's no web archive for that list so I can't point you to the >> | discussion. >> | > >> | > Anyway, this is clearly something no one has anticipated and the >> | question is whether we have a good way to solve that problem? >> | > >> | > Janek >> | > >> | > ----- Oryginalna wiadomość ----- >> | > Od: "Geoffrey Mainland" <mainland(a)apeiron.net> >> | > Do: "Jan Stolarek" <jan.stolarek(a)p.lodz.pl> >> | > DW: "ghc-devs" <ghc-devs(a)haskell.org> >> | > Wysłane: poniedziałek, 9 wrzesień 2013 15:40:09 >> | > Temat: Re: Alex and new Bool primops**** >> >> | > >> | > Perhaps the core libraries committee should reconsider their decision? >> | > :) Backwards compatibility is good. If HEAD implements the backwards >> | > compatibility plan that Simon PJ and I suggested and said plan is >> | > working, there should be a compelling reason to break compatibility >> | and >> | > have to go chasing down all the follow-on breakage (in, e.g., Alex) so >> | > close to release. >> | > >> | > What was the committee's reasoning? >> | > >> | > Geoff >> | > >> | > On 09/09/2013 10:08 AM, Jan Stolarek wrote: >> | >> I am refactoring new Bool primops (#6135). There was a discussion on >> | core-libraries-commitee list and the decision was made that we should >> | keep names of primops we used so far and change their type signature >> | (right now HEAD has different names for new primops and reuses old names >> | for compatibility wrappers). I've changed names of the primops and >> | removed the wrappers but I can't bootstrap GHC because old primops are >> | hardwired into Alex. I get this build error when attempting to build >> | stage 2 compiler: >> | >> >> | >> compiler/stage2/build/Lexer.hs:2348:34: >> | >> Couldn't match expected type 'Bool' with actual type 'Int#' >> | >> In the first argument of '(&&)', namely '(offset >=# 0#)' >> | >> In the expression: (offset >=# 0#) && (check ==# ord_c) >> | >> In the expression: >> | >> if (offset >=# 0#) && (check ==# ord_c) then >> | >> alexIndexInt16OffAddr alex_table offset >> | >> else >> | >> alexIndexInt16OffAddr alex_deflt s >> | >> >> | >> compiler/stage2/build/Lexer.hs:2348:53: >> | >> Couldn't match expected type 'Bool' with actual type 'Int#' >> | >> In the second argument of '(&&)', namely '(check ==# ord_c)' >> | >> In the expression: (offset >=# 0#) && (check ==# ord_c) >> | >> In the expression: >> | >> if (offset >=# 0#) && (check ==# ord_c) then >> | >> alexIndexInt16OffAddr alex_table offset >> | >> else >> | >> alexIndexInt16OffAddr alex_deflt s >> | >> >> | >> And indeed, looking at Lexer.hs I see: >> | >> >> | >> alex_scan_tkn user orig_input len input s last_acc = >> | >> (...) -- some irrelevant code here >> | >> (!(new_s)) = if (offset >=# 0#) && (check ==# ord_c) >> | >> then alexIndexInt16OffAddr alex_table >> | offset >> | >> else alexIndexInt16OffAddr alex_deflt s >> | >> >> | >> So to compile GHC, Alex would need to generate different code for GHC >> | 7.6.3 and below, and different for GHC 7.7 and above (or alternatively >> | it could generate #if pragmas), but this means we'd need to update Alex. >> | I created compatibility module within GHC called ExtsCompat46 and tried >> | adding it to list of imported modules, but in generated Lexer.hs Alex >> | adds a bunch of other modules among which is GHC.Exts, which conflicts >> | with import of ExtsCompat46: >> | >> >> | >> compiler/stage1/build/Lexer.hs:2349:41: >> | >> Ambiguous occurrence `>=#' >> | >> It could refer to either `ExtsCompat46.>=#', >> | >> imported from `ExtsCompat46' at >> | compiler/parser/Lexer.x:79:1-19 >> | >> or `GHC.Exts.>=#', >> | >> imported from `GHC.Exts' at >> | compiler/stage1/build/Lexer.hs:75:1-15 >> | >> (and originally defined in `ghc- >> | prim:GHC.Prim') >> | >> >> | >> Again, we would need updated version of Alex to generate correct code >> | (also, this would break in the future after removing that compatibility >> | module). I don't see a way out of this. Help? >> | >> >> | >> Janek >> | >> >> | >> _______________________________________________ >> | >> ghc-devs mailing list >> | >> ghc-devs(a)haskell.org >> | >> http://www.haskell.org/mailman/listinfo/ghc-devs >> | > >> | >> | >> | _______________________________________________ >> | ghc-devs mailing list >> | ghc-devs(a)haskell.org >> | http://www.haskell.org/mailman/listinfo/ghc-devs >> >> -- >> You received this message because you are subscribed to the Google Groups >> "haskell-core-libraries" group. >> To unsubscribe from this group and stop receiving emails from it, send an >> email to haskell-core-libraries+unsubscribe(a)googlegroups.com. >> For more options, visit https://groups.google.com/groups/opt_out.**** >> >> ** ** >> > >

1 0

A bug of linebuffering
by Kazu Yamamoto 10 Sep '13

10 Sep '13

Hi, While I support GHC head for "doctest", I encountered the following bug. "doctest" uses a GHCi subprocess to evaluate an expression represented in String. Stderr from GHCi is merged into stdout by hDuplicateTo in the GHCi side. Even evaluating an error expression, for instance "1 `div` 0", the line buffering does not work. "doctest" waits for output from GHCi forever. This does not happen if stderr is not merged into stdout. The following code demonstrates this bug. Running it with GHC head waits forever. Running it with GHC 7.6.3 prints: "*** Exception: divide by zero" "3" If you change "1 `div` 0" into "1 `div` 0\nprint 10", this code run by GHC head prints: "*** Exception: divide by zero" "10" This is a serious behavior change for "doctest". I hope this will be fixed. --Kazu module Main where import System.Process import System.IO myProc :: CreateProcess myProc = (proc "ghc" ["-v0", "--interactive", "-ignore-dot-ghci"]) { std_in = CreatePipe , std_out = CreatePipe , std_err = Inherit } setMode :: Handle -> IO () setMode hdl = do hSetBinaryMode hdl False hSetBuffering hdl LineBuffering newInterpreter :: IO (Handle, Handle) newInterpreter = do (Just stdin_, Just stdout_, _, _) <- createProcess myProc setMode stdin_ setMode stdout_ hPutStrLn stdin_ "import System.IO" hPutStrLn stdin_ "import GHC.IO.Handle" hPutStrLn stdin_ "hDuplicateTo stdout stderr" hFlush stdin_ return (stdin_, stdout_) eval :: Handle -> Handle -> String -> IO String eval hin hout expr = do hPutStrLn hin expr hFlush hin hGetLine hout main :: IO () main = do (stdin_, stdout_) <- newInterpreter eval stdin_ stdout_ "1 `div` 0" >>= print eval stdin_ stdout_ "1 + 2" >>= print return ()

1 1

the spam should stop now
by Carter Schonwald 10 Sep '13

10 Sep '13

I pingged the haskell infrastructure folks, and they've hopefully fixed it up properly.

1 0

如何构建人力资源管理系统
by 沛菡姐 10 Sep '13

10 Sep '13

4 3