RE: Confusing GHC error message
Yes, good point. I've improved the error message. It now reports a malformed class declaration. S | -Original Message- | From: George Russell [mailto:[EMAIL PROTECTED]] | Sent: 23 November 2001 13:22 | To: [EMAIL PROTECTED] | Subject: Confusing GHC error message | | | (Yes, I know that's not very impressive, but you must all | have been wondering what's happened to me.) | | The attached file, when compiled with ghc5.02.1, | -fglasgow-exts -fallow-overlapping-instances | -fallow-undecidable-instances produces the error message |Haskell.hs:11: Illegal left hand side in data/newtype | declaration This is rather confusing, as the error comes not | from the data declaration in the file, but because on the | next line class was accidentally typed, rather than instance. | ___ Glasgow-haskell-bugs mailing list [EMAIL PROTECTED] http://www.haskell.org/mailman/listinfo/glasgow-haskell-bugs
RE: (no subject)
i use green-card with ghc's FFI export to sth like Haskell - C -- Haskell the program is just arithmatic operations. the program seg fault in the callback from C to Haskell. anyone whether it is a bug? There aren't any known bugs, but there are many known pitfalls. You'll need to give us more information, at least: the code that causes the crash (preferably a small example), the exact GHC command lines used to compile it, your GHC version, your machine and OS version. Cheers, Simon ___ Glasgow-haskell-users mailing list [EMAIL PROTECTED] http://www.haskell.org/mailman/listinfo/glasgow-haskell-users
RE: GHC garbage collector
I have some code that uses FFI capabilities to associate previously allocated memory with a structure akin to a ByteArray and allows Haskell land to read and write to the C side of things. I use ForeignPtr and associate a destructor to allow the GHC's garbage collector to clean up after it figures out that the structure is no longer being used. I know I am in funny territory. In some instances (when benchmarking) GHC takes its time getting around to garbage collecting. Can someone suggest hooks to encourage GHC to clean up things? Or better still functions to instruct GHC to garbage collect specific structures (by calling relevant destructors)? Also comments on how safe this whole business is. IOExts.performGC will cause a full garbage collection to be performed. If you want to be sure the finalizer has run to completion, you'll need to set up some synchronisation between the main thread and the finalizer using MVars. Finalizers have no special scheduling properties; they just run concurrently with the other threads in the system. Cheers, Simon ___ Glasgow-haskell-users mailing list [EMAIL PROTECTED] http://www.haskell.org/mailman/listinfo/glasgow-haskell-users
RE: (no subject)
hi, i've found the reason with someone's help. it is because i used %code instead of safecode in the gc file where i did callback. thanks! chenyu -- Original Message -- From: Simon Marlow [EMAIL PROTECTED] Date: Mon, 26 Nov 2001 09:42:39 - i use green-card with ghc's FFI export to sth like Haskell - C -- Haskell the program is just arithmatic operations. the program seg fault in the callback from C to Haskell. anyone whether it is a bug? There aren't any known bugs, but there are many known pitfalls. You'll need to give us more information, at least: the code that causes the crash (preferably a small example), the exact GHC command lines used to compile it, your GHC version, your machine and OS version. Cheers, Simon ___ Glasgow-haskell-users mailing list [EMAIL PROTECTED] http://www.haskell.org/mailman/listinfo/glasgow-haskell-users
Re: Socket library ghc 5.02.1
Sven Eric Panitz [EMAIL PROTECTED] writes: It seems that the Socket library does still not work with ghc 5.02.1. I tried the simple test: main = do d - connectTo localhost (PortNumber 80) hPutStr d GET / HTTP/1.0\n\n hFlush d c - hGetContents d putStr c On Windows2000 I get the known error: *** Exception: does not exist Action: getProtocolByName Reason: no such protocol entry (You, of course, need to wrap up that code with Socket.withSocketDo to start up WinSock first). FYI, in case you're planning on doing socket programming with GHC-5.02 on a Win32 platform, stay away from using the higher-level Socket module, since its IO.Handle based view of sockets is just broken. Stick with the lower-level SocketPrim interface instead. Specifically, stay away from using the following: * Socket. connectTo * Socket.accept * Socket.sendTo * Socket. recvFrom * SocketPrim.socketToHandle --sigbjorn ___ Glasgow-haskell-users mailing list [EMAIL PROTECTED] http://www.haskell.org/mailman/listinfo/glasgow-haskell-users
RE: heap and walking through a very long list
You can do it specifically for GHC, not not in standard Haskell (except grossly inefficiently). To see how to do it in GHC, look at the implementation in the source code (ghc/lib/std), which is online (check the CVS repository link on GHC's home page). Meanwhile you could use the IArray stuff. Simon | -Original Message- | From: Joe English [mailto:[EMAIL PROTECTED]] | Sent: 25 November 2001 00:12 | To: [EMAIL PROTECTED] | Subject: Re: heap and walking through a very long list | | | | Simon Peyton-Jones wrote: | | There should really be a strict accumArray, just as there | should be a | strict foldl. | | Yes, please! | | Is there a way to write a strict version of accumArray in | Haskell 98, or does this need to be done by the implementation? | | | --Joe English | | [EMAIL PROTECTED] | | ___ | Haskell mailing list | [EMAIL PROTECTED] http://www.haskell.org/mailman/listinfo/haskell | ___ Haskell mailing list [EMAIL PROTECTED] http://www.haskell.org/mailman/listinfo/haskell
Library report examples
Hi guys, The library report defines -- Diagonal of a square matrix diag :: (Ix a) = Array (a,a) b - Array a b diag x = ixmap (l,u) (\i-(i,i)) x where ((l,l'),(u,u')) | l == l' u == u' = bounds x but ghc, hugs and nhc98 all loop (trying to get and test the value of l I believe). I am also curious why, for example, row :: (Ix a, Ix b) = a - Array (a,b) c - Array b c row i x = ixmap (l',u') (\j-(i,j)) x where ((l,l'),(u,u')) = bounds x isn't written as row :: (Ix a, Ix b) = a - Array (a,b) c - Array b c row i x = ixmap (l,u) (\j-(i,j)) x where ((_,l),(_,u)) = bounds x ~~~~~~ ~~~ Thanks Ian ___ Haskell mailing list [EMAIL PROTECTED] http://www.haskell.org/mailman/listinfo/haskell
List module in library report exports []((:), [])
Hiyas A few more things I'm afraid :-( The List module in the library report exports []((:), []) which, as I mentioned in a previous thread WRT the GHC prelude, the report doesn't allow in the exports list. The block at the top listing the exports and types has been split into 2 at an apparently arbitrary point for no obvious reason? deleteFirstsBy has no corresponding deleteFirsts and is not mentioned in the text. Actually, having looked at the definitions it seems to be what we would like to call \\By, so this should be noted in the By section. insert and the zip/unzip stuff is also not explained in the text - don't know if this is deliberate or not (insert is also mentioned with sort). sortBy is mentioned before the By section unlike the other By variants for no obvious reason. exmaple genericIndex seems to be a generic !!, but The prefix generic indicates an overloaded function that is a generalised version of a Prelude function. and index is something completely different and defined in Ix. Clearly the function can't be called generic!!, so I suggest the non-uniformity be noted. I am also curious as to why other functions don't have generic equivalents, e.g. elemIndex, findIndices - is it because they were also not considered important enough (as per the By functions)? The indentation of unfoldr, maximumBy and minimumBy seems to have gone wrong with some things not being indented at all (only looked at the HTML version). I think unionBy eq xs ys = xs ++ foldl (flip (deleteBy eq)) (nubBy eq ys) xs may be clearer written as unionBy eq xs ys = xs ++ deleteFirstsBy eq (nubBy eq ys) xs Thanks Ian ___ Haskell mailing list [EMAIL PROTECTED] http://www.haskell.org/mailman/listinfo/haskell
Re: Asynchronous Exceptions
Hello! On Fri, Nov 23, 2001 at 09:38:35AM -, Simon Marlow wrote: [...] However, I agree that sometimes you really want to be able to do this, so perhaps we need another form of 'block' which doesn't allow *any* exceptions to be delivered, for those times when you know that the time spent waiting in an interruptible operation is going to be bounded. But even things like putStr can block for an unbounded amount of time. E.g. stdout is a pipe and the reader just doesn't read it for n hours (n unknown), etc. Kind regards, Hannah. ___ Haskell mailing list [EMAIL PROTECTED] http://www.haskell.org/mailman/listinfo/haskell
