[Haskell-cafe] Gtk2Hs + Sourceview on Windows
Hi, I have ghc 6.10.1 and gtk2hs 0.10.0 installed on my windows vista computer. Both were installed using the installer on the webpages. I am able to use gtk, glade etc but not sourceview or cairo. If I compile the examples in the gtk2hs example folder, I get not in scope error messages for functions from those library components. In a forum I found that those have to be enabled using ./configure --enable-sourceview (similar for cairo). But my windows installation does not seem to have a script configure or a similar program. What am I supposed to do? Thanks, Michael -- Michael WinterBrock University Associate Professor500 Glenridge Avenue Department of Computer Science St. Catharine, ON, L2S 3 A1 Phone: +1 905 688 5550 ext 3355 Fax: +1 905 688 3255 - ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] Parsec - Custom Fail
Hi,
I am using parsec to parse a small programming language. The language is typed
and
I need to do some type checking, too. I have decided to do the parsing and type
checking
simultaneously in the my parsec parser. This approach avoids to keep source
code positions
in the data type in order to produce suitable error messages during type
checking. Anyhow,
because type errors are usually detected after parsing some code I need produce
error
messages with an earlier source position. Unfortunately, there is no function
that produces
an error taking a position as parameter.
I tried the following:
myFail :: SourcePos - String - GenParser tok st a
myFail pos msg = setPosition pos fail msg
This is already a workaround because I am modifying the position in the parser
just to
produce an error message. But even worse, it does not work. If I use this
function as in:
test :: Either ParseError ()
test = runParser (char '(' myFail (newPos 100 100) Test) () (
the position of the error is still the original position (line 1, column 2). As
far as I can tell
setPosition does not take effect until another symbol is read. This could be
achieved by
simply using anyToken if we are not at the end of the input (as in the example
above). I
came up with the following:
myFail :: SourcePos - String - GenParser Char st a
myFail pos msg = do {
State toks _ st - getParserState;
setParserState $ State ('d':toks) pos st;
anyToken;
fail msg
}
This code works but it is not nice at all. The function myFail is not longer
polymorphic in
the type of tokens since we need an element of this data type in order to add
it temporarily
to the input ('d' above).
My guess is that one has to enforce strictness at some point in order to work
with the first
approach, but I was not successful. Any ideas?
Thanks,
Michael
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Re: [Haskell-cafe] Parsec - Custom Fail
Thanks, but I want a nice solution not another, even more complicated, workaround. On 5 May 2009 at 17:10, Martijn van Steenbergen wrote: mwin...@brocku.ca wrote: Hi, I am using parsec to parse a small programming language. The language is typed and I need to do some type checking, too. I have decided to do the parsing and type checking simultaneously in the my parsec parser. This approach avoids to keep source code positions in the data type in order to produce suitable error messages during type checking. Anyhow, because type errors are usually detected after parsing some code I need produce error messages with an earlier source position. Unfortunately, there is no function that produces an error taking a position as parameter. If you already know what position you want to report the error at, then why bother calling setPosition to let parsec know? Just do: fail (show pos ++ : ++ msg) Parsec will then result in a ParseError with its own ideas of location, but you can ignore that. HTH, Martijn. ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] Threading and Mullticore Computation
Hi, I tried a get into concurrent Haskell using multiple cores. The program below creates 2 task in different threads, executes them, synchronizes the threads using MVar () and calculates the time needed. import System.CPUTime import Control.Concurrent import Control.Concurrent.MVar myTask1 = do return $! fac 6 print Task1 done! where fac 0 = 1 fac n = n * fac (n-1) myTask2 = do return $! fac' 6 1 1 print Task2 done! where fac' n m p = if mn then p else fac' n (m+1) (m*p) main = do mvar - newEmptyMVar pico1 - getCPUTime forkIO (myTask1 putMVar mvar ()) myTask2 takeMVar mvar pico2 - getCPUTime print (pico2 - pico1) I compiled the code using $ ghc FirstFork.hs -threaded and executed it by $ main +RTS -N1 resp. $ main +RTS -N2 I use GHC 6.8.3 on Vista with an Intel Dual Core processor. Instead of getting a speed up when using 2 cores I get as significant slow down, even though there is no sharing in my code above (at least none I am aware of. BTW, that was reason that I use 2 different local factorial functions). On my computer the 1-core version takes about 8.3sec and the 2-core version 12.8sec. When I increase the numbers from 6 to 10 the time difference gets even worse (30sec vs 51 sec). Can anybody give me an idea what I am doing wrong? Thanks, Michael ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Threading and Mullticore Computation
In both runs the same computations are done (sequentially resp. parallel), so the gc should be the same. But still using 2 cores is much slower than using 1 core (same program - no communication). On 3 Mar 2009 at 20:21, Bulat Ziganshin wrote: Hello mwinter, Tuesday, March 3, 2009, 8:09:21 PM, you wrote: anybody give me an idea what I am doing wrong? 1. add -O2 to compile command 2. add +RTS -s to run commands your program execution time may be dominated by GCs -- Best regards, Bulatmailto:bulat.zigans...@gmail.com ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Threading and Mullticore Computation
It gets a bit faster in general but the problem remains. I have two threads in both runs, once I use 1 core and then 2 cores. The second run is much slower. On 3 Mar 2009 at 17:32, Sebastian Sylvan wrote: On Tue, Mar 3, 2009 at 5:31 PM, mwin...@brocku.ca wrote: In both runs the same computations are done (sequentially resp. parallel), so the gc should be the same. But still using 2 cores is much slower than using 1 core (same program - no communication). Might there not be contention in the allocator/GC that's worsened by having two threads? What happens with -O2? -- Sebastian Sylvan +44(0)7857-300802 UIN: 44640862 ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Threading and Mullticore Computation
I am using GHC 6.8.3. The -O2 option made both runs faster but the 2 core run is still much slower that the 1 core version. Will switching to 6.10 make the difference? On 3 Mar 2009 at 18:46, Svein Ove Aas wrote: On Tue, Mar 3, 2009 at 6:41 PM, Don Stewart d...@galois.com wrote: allbery: On 2009 Mar 3, at 12:31, mwin...@brocku.ca wrote: In both runs the same computations are done (sequentially resp. parallel), so the gc should be the same. But still using 2 cores is much slower than using 1 core (same program - no communication). The same GCs are done, but GC has to be done on a single core (currently; parallel GC is in development) so you will see a lot more lock contention when the GC kicks in. Assuming he is using GHC 6.10, the parallel GC is enabled by default when you use -Nn where n 1. That's is -N4 will use -g4 (4 cores to collect). So GC should be the same or a little faster. Further, GHC (6.10 at least) uses one allocation area per thread, meaning there's no contention on allocation. I'd echo the request to try it with -O2, though. ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
