November 2002 - Glasgow-haskell-users

RE: Nightly build snapshots available
by Simon Marlow 08 Nov '02

08 Nov '02

> At 2002-11-07 06:10, Ralf Hinze wrote: > > >I would appreciate a little note saying "this snapshot is ok", > >or "this one is horribly broken", or maybe "this one is a milestone", > >if this is at all possible. > > Heh, I suspect that's for us to find out... Well, most of the time you know as much as me :-) I don't want to tag each snapshot with a personal certification of stability because (a) most of the time I have no idea, (b) it's extra work (I went to a lot of trouble to automate all this), (c) there are likely to be cases exercised by your code but not by any of our tests, and (d) the nightly build logs contain a nice testing report stating which tests failed for each snapshot. Currently, for example, we're running at about 7 test case failures out of 3000-ish, and these failures are mostly harmless (floating-point differences when programs are compiled with the native code generator). The compiler is relatively stable at the moment, but your mileage may vary... (PS sorry about the lack of a source dist from last night's build again, hopefully it'll appear tonight). Cheers, Simon

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RE: crash in profiling mode
by Simon Marlow 08 Nov '02

08 Nov '02

> Another question: The profiling mode of GHC-4.08.2 did also output (in > mode +RTS -p) the time spent on garbage collection (as an additional > percentage of overall running time). > With the programs I tested so far under GHC-5.04.1, I never > saw such an > indication in a.out.prof, although for the same programs under > GHC-4.08.2 considerable garbage collection times were measured. > > Does this mean that: > > a) the indication of garbage collection times has been dropped from > profiling reports (can I obtain them in another way?), > > or > > b) the newer GHC is so smart that it optimised away the need for > garbage collection in the particular (few) programs I tested, but > otherwise the GC times will show up in profiling reports, > > or > > c) something else? The inclusion of GC time in the report was wrong, since GC time wasn't included in the figure for total time, so you could get GC times of > 100%. You can get a measure of GC time vs. mutator time by adding '+RTS -sstderr' to the command line. Cheers, Simon

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Re: Nightly build snapshots available
by Ashley Yakeley 07 Nov '02

07 Nov '02

At 2002-11-07 06:10, Ralf Hinze wrote: >I would appreciate a little note saying "this snapshot is ok", >or "this one is horribly broken", or maybe "this one is a milestone", >if this is at all possible. Heh, I suspect that's for us to find out... -- Ashley Yakeley, Seattle WA

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Re : Extensible records in Haskell
by Nicolas Oury 07 Nov '02

07 Nov '02

> > Hello, is there something like extensible records in ghc? >Are you wanting something like Hugs' T-Rex or did you have something >else in mind? Hello, For what I understand of T-Rex it is what I wait. I need something that can allow to use records without declaring their type first and that can be extended by creating a new records with the same contents plus one or less one. Best regards, Nicolas

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GHCi on Mac OS X
by Felix Reckers 07 Nov '02

07 Nov '02

When I start the ghci with -package data, I get the following output: Loading package base ... linking ... done. Loading package haskell98 ... linking ... done. Loading package lang ... linking ... done. Loading package concurrent ... linking ... done. Loading package posix ... linking ... done. Loading package util ... linking ... not found: _rl_funmap_names Abort I know that I must install the readline library seperately; can anybody tell me how to do this? Felix Reckers

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RE: specifing user RTS options to GHCi
by Simon Marlow 07 Nov '02

07 Nov '02

> I would like to be able to use the -xc option in ghci, since > this is where > I do most of my debugging anyway. I can put > > :set -prof -auto-all > :set -osuf prof.sun4.o -hisuf prof.sun4.hi > > in my .ghci file, but I can't get ghci to run my code with -xc > enabled. If I try to ":set +RTS -xc", ghci doesn't know this > options; if > I pass then to ghci on the commandline (i.e., "% ghci +RTS -xc") it > (rightfully) tells me that ghci wasn't built for profiling. > > Is there any way to do this and, if not, might it find its way in? I'm afraid there isn't a way to do this. The long answer: GHCi runs the interpreted code on top of the same RTS as it is running itself, and for -xc to work, that means the RTS has to be a profiling version. The profiled version of the RTS differs from the normal version in several ways: heap objects have an extra field, info tables have extra fields, and so on. The bytecode compiler and interpreter don't have the necessary knowledge to generate and run bytecode in this different environment. > p.s., I think the -xc option is seriously undervalued -- I know that I > didn't know about it for about a year of using ghc even after > asking if > such a thing could be done in various places (clf, mostly). Yes, we should probably advertise it more. Please feel free to send us documentation patches... > Perhaps it should go in the option list for +RTS? It is in the option list for +RTS - but only when the binary is compiled for profiling. Cheers, Simon

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specifing user RTS options to GHCi
by Hal Daume III 07 Nov '02

07 Nov '02

I would like to be able to use the -xc option in ghci, since this is where I do most of my debugging anyway. I can put :set -prof -auto-all :set -osuf prof.sun4.o -hisuf prof.sun4.hi in my .ghci file, but I can't get ghci to run my code with -xc enabled. If I try to ":set +RTS -xc", ghci doesn't know this options; if I pass then to ghci on the commandline (i.e., "% ghci +RTS -xc") it (rightfully) tells me that ghci wasn't built for profiling. Is there any way to do this and, if not, might it find its way in? - Hal p.s., I think the -xc option is seriously undervalued -- I know that I didn't know about it for about a year of using ghc even after asking if such a thing could be done in various places (clf, mostly). Perhaps it should go in the option list for +RTS? -- Hal Daume III "Computer science is no more about computers | hdaume(a)isi.edu than astronomy is about telescopes." -Dijkstra | www.isi.edu/~hdaume

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RE: Re : Extensible records in Haskell
by Simon Peyton-Jones 07 Nov '02

07 Nov '02

The TRex record system is probably the main type-system extension that GHC does not currently implement. The trouble is that it's quite a bit of work. If it were just the type inference part it would be ok, but it requires new primitive operations to insert fields in records, and I think that interacts with GHC's current data structure representations. So it's feasible but it's Real Work. So far, to my surprise, no one has asked for it. You are nearly the first! Another reason for holding back is that Mark and I worked out a design, in the light of TRex (see our paper at the Haskell workshop '99), but it'd be a pity to have Hugs and GHC differing.... and I'm not sure that anyone would have enough energy to change Hugs. So for a variety of reasons, I'm inclined to leave it as a Good Reason To Use Hugs, but I could probably be persuaded otherwise. Simon | -----Original Message----- | From: Nicolas Oury [mailto:Nicolas.Oury@ens-lyon.fr] | Sent: 06 November 2002 08:38 | To: glasgow-haskell-users(a)haskell.org | Subject: Re : Extensible records in Haskell | | > > Hello, is there something like extensible records in ghc? | | >Are you wanting something like Hugs' T-Rex or did you have something | >else in mind? | | | Hello, | For what I understand of T-Rex it is what I wait. | | I need something that can allow to use records without declaring their | type first and that can be extended by creating a new records with the | same contents plus one or less one. | | Best regards, | Nicolas | | _______________________________________________ | Glasgow-haskell-users mailing list | Glasgow-haskell-users(a)haskell.org | http://www.haskell.org/mailman/listinfo/glasgow-haskell-users

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Nightly build snapshots available
by Simon Marlow 07 Nov '02

07 Nov '02

As requested by several people, we're now making source snapshots of GHC available every night, together with some binary distributions (only x86-linux to begin with) built by the nightly build system. Pointers to the snapshots are on GHC's download page, here: http://www.haskell.org/ghc/download.html Note that there aren't any source distributions yet, but they will start to appear from tonight. Enjoy... Simon

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Re: Re: Extensible records in Haskell
by Keean Schupke 07 Nov '02

07 Nov '02

Thanks, have read the paper, however also saw the paper by Simon Peyton-Jones and Mark Jones on Lightweight Extensible Records for Haskell, which I think Simon refered to in an earlier post... would it not be better to have this instead? Regards, Keean Schupke. Alastair Reid wrote: >> Actually this raises an interesting point - As far as I can see >> you can do anything you can do with TRex, using a FiniteMap of >> Dynamic. How is TRex different from this? Is TRex just syntactic >> sugar for this kind of construct? >> > > > Read the paper (on Mark Jones publications page). > > Trex is statically typed. > > You could certainly get the effect of Haskell typeclasses using a > FiniteMap of Dynamic to store methods (this isn't too far from what > Smalltalk does) but it wouldn't be statically typed. Trex uses > mechanisms close to those used to implement typeclasses to implement > extensible records. > > -- > Alastair > > >

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