December 2005 - Glasgow-haskell-users

RE: [STM] Better name for waitUntil?
by Simon Marlow 23 Dec '05

23 Dec '05

On 19 December 2005 09:43, Tomasz Zielonka wrote: > On Mon, Dec 19, 2005 at 09:34:19AM -0000, Simon Peyton-Jones wrote: >> waitUntil sounds like a plausible name. > > But how do I name "itsBefore"? > dontWaitUntil? ;-) > >> Better than itsAfter or timeAfter. > >> But perhaps sleepUntil would be better, because it's a variant of >> sleep? > > Well yes, but an STM compatible one, so you can simultaneously > waitUntil and try to read from channel, and you get whatever > happens first. > Also, the interface is entirely in STM - no need to initialize the > timer in IO. Simon Marlow gave a nice example for usefulness of this: >> Interesting. You could use that do wait for idle time, for example: >> >> atomically $ do >> t <- readTVar last_mouse_click >> waitUntil (t+1000) >> ... >> >> so this transaction only completes when some idle time has passed >> since the last mouse click. > > Let's assume I am going to implement itsBefore (seems to be quite > straightforward), so I want a pair of opposite names. Some > variations: > > itsAfter / itsBefore > guardTimeAfter / guardTimeBefore > waitUntil / ??? How about retryIfEarlierThan / retryIfLaterThan retryIfBefore / retryIfAfter I like making it clear that the operation behaves like retry given certain conditions. Cheers, Simon

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RE: Preferred way of submitting patches
by Simon Marlow 23 Dec '05

23 Dec '05

On 17 December 2005 16:21, Einar Karttunen wrote: > What is the preferred way of submitting patches at the moment? > I tried using Trac but it seems that users without an account > on haskell.org cannot attach files... Is using Trac and > linking to the patch hosted externally the way to go? I think I've now tweaked the permissions to allow anonymous users to attach files. Please have a go. Cheers, Simon

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RE: Preferred way of submitting patches
by Simon Peyton-Jones 21 Dec '05

21 Dec '05

Einar Simon M's on holiday for Xmas; but he's the man to answer this when he gets back. Simon | -----Original Message----- | From: glasgow-haskell-users-bounces(a)haskell.org [mailto:glasgow-haskell-users- | bounces(a)haskell.org] On Behalf Of Einar Karttunen | Sent: 17 December 2005 16:21 | To: glasgow-haskell-users(a)haskell.org | Subject: Preferred way of submitting patches | | Hello | | What is the preferred way of submitting patches at the moment? | I tried using Trac but it seems that users without an account | on haskell.org cannot attach files... Is using Trac and | linking to the patch hosted externally the way to go? | | - Einar Karttunen | _______________________________________________ | Glasgow-haskell-users mailing list | Glasgow-haskell-users(a)haskell.org | http://www.haskell.org/mailman/listinfo/glasgow-haskell-users

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RE: instance inference
by Simon Peyton-Jones 19 Dec '05

19 Dec '05

Martin Sulzmann is the world expert on this stuff. Maybe he'll know. Simon | -----Original Message----- | From: glasgow-haskell-users-bounces(a)haskell.org [mailto:glasgow-haskell-users- | bounces(a)haskell.org] On Behalf Of Ross Paterson | Sent: 19 December 2005 10:16 | To: Simon Peyton-Jones | Cc: glasgow-haskell-users(a)haskell.org | Subject: Re: instance inference | | As a termination test, how about no restrictions on context and head | except: | | Each assertion in the context must satisfy | * the variables of the assertion are a sub-multiset of those of the | head (though they may be the same), and | * the assertion has fewer type constructors and variables (taken | together and counting repetitions) than the head. | | This ensures that under any ground substitution the context assertion has | fewer type constructors than the head. | | It would accept all instances accepted by the current test, plus | | instance C a | instance C (s a) => C (Sized s a) | instance (C1 a, C2 b) => C a b | instance C1 Int a => C2 Bool [a] | instance C1 Int a => C2 [a] b | instance C a a => C [a] [a] | | But not things like | | instance (C1 a, C2 a, C3 a) => C a | | because that would need to check other instances as well. | | _______________________________________________ | Glasgow-haskell-users mailing list | Glasgow-haskell-users(a)haskell.org | http://www.haskell.org/mailman/listinfo/glasgow-haskell-users

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RE: [STM] Better name for waitUntil?
by Simon Peyton-Jones 19 Dec '05

19 Dec '05

waitUntil sounds like a plausible name. Better than itsAfter or timeAfter. But perhaps sleepUntil would be better, because it's a variant of sleep? Simon | -----Original Message----- | From: glasgow-haskell-users-bounces(a)haskell.org [mailto:glasgow-haskell-users- | bounces(a)haskell.org] On Behalf Of Tomasz Zielonka | Sent: 19 December 2005 09:28 | To: GHC-users | Subject: [STM] Better name for waitUntil? | | Hello! | | I am finishing my waitUntil implementation for STM. It's a new | STM action that will allow to wait for a given time point. | | waitUntil :: UTCTime -> STM () | | (UTCTime is from Ashley Yakeley's Time library.) | | The intended semantics is that | | waitUntil t | | will succeed as soon as time passes t, or more precisely when (now >= t). | | Right now I am to find a better name for waitUntil. Maybe it should be | more declarative, like "itsAfter" or "timeAfter"? I am not a native english | speaker, so I am probably missing many options. Any ideas? | | I also think about adding something like "itsBefore", which would mean | (now < t). | | How about "it'sAfter" ? | Maybe only "after", without "it's" ? | | Thanks in advance for your help. | | PS. I imagine that it would be possible to implement waitUntil more | efficiently in GHC's RTS, but my implementation can be a nice | showcase for STM's expressivity, and it's still quite efficient | (I used some (quite elegant :) hacks to implement subsecond | precision waitUntil efficiently). | | Best regards | Tomasz | | -- | I am searching for a programmer who is good at least in some of | [Haskell, ML, C++, Linux, FreeBSD, math] for work in Warsaw, Poland | _______________________________________________ | Glasgow-haskell-users mailing list | Glasgow-haskell-users(a)haskell.org | http://www.haskell.org/mailman/listinfo/glasgow-haskell-users

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[STM] Better name for waitUntil?
by Tomasz Zielonka 19 Dec '05

19 Dec '05

Hello! I am finishing my waitUntil implementation for STM. It's a new STM action that will allow to wait for a given time point. waitUntil :: UTCTime -> STM () (UTCTime is from Ashley Yakeley's Time library.) The intended semantics is that waitUntil t will succeed as soon as time passes t, or more precisely when (now >= t). Right now I am to find a better name for waitUntil. Maybe it should be more declarative, like "itsAfter" or "timeAfter"? I am not a native english speaker, so I am probably missing many options. Any ideas? I also think about adding something like "itsBefore", which would mean (now < t). How about "it'sAfter" ? Maybe only "after", without "it's" ? Thanks in advance for your help. PS. I imagine that it would be possible to implement waitUntil more efficiently in GHC's RTS, but my implementation can be a nice showcase for STM's expressivity, and it's still quite efficient (I used some (quite elegant :) hacks to implement subsecond precision waitUntil efficiently). Best regards Tomasz -- I am searching for a programmer who is good at least in some of [Haskell, ML, C++, Linux, FreeBSD, math] for work in Warsaw, Poland

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Preferred way of submitting patches
by Einar Karttunen 17 Dec '05

17 Dec '05

Hello What is the preferred way of submitting patches at the moment? I tried using Trac but it seems that users without an account on haskell.org cannot attach files... Is using Trac and linking to the patch hosted externally the way to go? - Einar Karttunen

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RE: Preparing a Registered hc-file-bundle (Was BootstrappingwithHCfiles)
by Simon Marlow 16 Dec '05

16 Dec '05

On 15 December 2005 16:19, Andrew Walrond wrote: > Hi Simon, > > On Wednesday 14 December 2005 09:49, Simon Marlow wrote: >> Actually, looking at ghc/Makefile, it is possible that ghc/lib isn't >> getting built early enough. Try changing: >> >> SUBDIRS = includes rts docs compiler lib utils driver >> >> to >> >> SUBDIRS = includes rts lib docs compiler utils driver >> > > Did that. Now I get to here: > > ------------------------------------------------------------------------ > ===fptools== Recursively making `all' in compat ... > PWD = /home/andrew/test/ghc/bs/target/ghc-6.4.1/ghc/lib > ------------------------------------------------------------------------ > ------------------------------------------------------------------------ > ==fptools== make all - --no-print-directory -r; > in /home/andrew/test/ghc/bs/target/ghc-6.4.1/ghc/lib/compat > ------------------------------------------------------------------------ > make[2]: *** No rule to make target `Compat/Directory.o', needed by > `ghccompat.o'. Stop. > make[1]: *** [all] Error 1 > make: *** [all] Error 1 > make: Leaving directory > `/home/andrew/test/ghc/bs/target/ghc-6.4.1/ghc' > > Any clues how to proceed? I have no idea what has gone wrong here. We ought to be able to make Compat/Directory.o. However, we don't need ghccompat.o, so you could try adding: GhcWithInterpter=NO to ghc/lib/compat/Makefile, right after the NO_INSTALL_LIBRARY setting. If that doesn't work, please run 'make -p -d' in ghc/lib/compat and send me the output. Cheers, Simon

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RE: utf8 strings: memory optimization and case-ignoring comparision
by Simon Marlow 16 Dec '05

16 Dec '05

On 14 December 2005 20:35, Bulat Ziganshin wrote: > i use utf8-packed strings in my program and have to ask 2 questions > about them: > > 1. i need function to do case-ignoring comparision of such strings. > stricmp is not appropriate because it don't know about utf8. can be > the existing Unicode support in Data.Char used for these or can the > appropriate support will be added? you should be able to use toUpper/toLower from Data.Char in GHC 6.4.1. > 2. what is the most memory-efficient representaion for such strings? > now i use John Meacham's library > (http://repetae.net/john/repos/jhc/PackedString.hs) which declares: > > newtype PackedString = PS (UArray Int Word8) > > but this uses two Ints just to hold index bounds: > > data UArray i e = UArray !i !i ByteArray# I don't know why an extra 8/16 bytes per string is that worrying - if you have so many small strings perhaps you should be sharing them via a hash table? > i want to use just memory ptr and put NUL at the end of array (my > strings never contain NUL chars). but what type i must use for this > ptr? ByteArray/ByteArray#, ForeignPtr, StablePtr, Ptr?? and which > function > i must use to quickly allocate memory i need? my packed strings will > be only unpacked and passed to "unsafe" C functions: stricmp, strcpy, > strcat; i plan to not use any other operations ForeignPtr and mallocForeignPtr are the way to go these days. In GHC 6.6 these will be much faster than before. Cheers, Simon

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RE: Preparing a Registered hc-file-bundle (Was Bootstrapping withHCfiles)
by Simon Marlow 15 Dec '05

15 Dec '05

On 14 December 2005 09:46, Simon Marlow wrote: > On 13 December 2005 18:58, Andrew Walrond wrote: > >> Well, I gave it a blast anyway. All went well creating the hc files >> until the last command: >> >>> $ make hc-file-bundle Project=Ghc >> >> at which point it failed with >> >> tar czf ghc-6.4.1-x86_64-unknown-linux-hc.tar.gz `cat hc-files-to-go` >> tar: ghc-6.4.1/ghc/rts/AutoApply_thr.hc: Cannot stat: No such file >> or directory tar: ghc-6.4.1/ghc/rts/AutoApply_thr_p.hc: Cannot stat: >> No such file or directory tar: ghc-6.4.1/ghc/rts/AutoApply_debug.hc: >> Cannot stat: No such file or directory tar: Error exit delayed from >> previous errors >> make: *** [hc-file-bundle] Error 2 > > Yes, these are harmless. They are caused by the fact that > AutoApply.cmm is auto-generated in several different ways > (AutoApply_thr.cmm, AutoApply_debug.cmm etc.), and the .hc files for > these are named AutoApply_thr.thr_hc, AutoAPply_debug.debug_hc, and > so on. The Makefile code for hc-bundle doesn't know about this > special case. > >> Googling suggests this might be harmless, so I tried bootstrapping on >> the target machine using the created tarball, but that failed with >> >> /bin/ld: cannot find -lghccompat >> collect2: ld returned 1 exit status >> make[1]: *** [stage1/ghc-6.4.1] Error 1 >> make: *** [all] Error 1 >> make: Leaving directory >> `/home/andrew/test/ghc/bs/target/ghc-6.4.1/ghc' > > Please send us a full log of the build. libghccompat.a should be in > ghc/lib/compat, and it should be built quite early on. Actually, looking at ghc/Makefile, it is possible that ghc/lib isn't getting built early enough. Try changing: SUBDIRS = includes rts docs compiler lib utils driver to SUBDIRS = includes rts lib docs compiler utils driver Cheers, Simon

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