Um... you do realize that the code is only supposed to match against
very specific lines in sample data sets that Bray provides, right? If
your access log doesn't have lines exactly like those (and why would
it?) then there's no reason to expect a result.
--S
On Nov 9, 2007, at 11:19 PM, Berlin Brown wrote:
Sterling Clover wrote:
I hacked together a version that I'm pretty happy with today.
Started off trying an algorithm with channels and forking, then
realized that in Haskell thanks to referential transparency we can
get parallelism almost for free, and redid it all in
Control.Parallel (below). Unfortunately, I don't have a multicore
processor so I can't put this through any special paces. However,
its compactness and expressively match or beat the simple Ruby,
etc. scripts while it gets (theoretically) most of the parallel
benefits of the enormous and unwieldy Erlang and JOcaml ones.
--S
module Main where
import qualified Data.ByteString.Lazy.Char8 as LB
import Data.List (foldl', unfoldr, insertBy)
import qualified Data.Map as M
import System.Environment (getArgs)
import Control.Parallel (par)
import Control.Parallel.Strategies (parMap, rwhnf)
count :: M.Map LB.ByteString Int -> LB.ByteString -> M.Map
LB.ByteString Int
count m line = if LB.pack "/ongoing/When" `LB.isPrefixOf` myLn
then M.insertWith' (+) (LB.drop 14 myLn) 1 m else m
where myLn = (LB.takeWhile (/=' ') . LB.dropWhile (/='/') .
LB.dropWhile (/='\"')) line
mapUnionPar :: (Ord k, Num a) => [M.Map k a] -> M.Map k a
mapUnionPar m = head $ until (null . tail) mapUnionPar' m
where a |:| b = par a . par b $ a : b
mapUnionPar' (x:x':xs) = (M.unionWith (+) x x' |:| mapUnionPar' xs)
mapUnionPar' x = x
newPar :: FilePath -> IO (M.Map LB.ByteString Int)
newPar = ((mapUnionPar . parMap rwhnf (foldl' count M.empty) .
chunkify . LB.lines) `fmap`) . LB.readFile
where chunkify = unfoldr (\x -> if null x then Nothing else Just
(splitAt 512 x))
main = mapM_ ((print . fst . foldl' takeTop ([],[]) . M.toList
=<<) . newPar) =<< getArgs
where takeTop ac@(bs,low) a = if null low || (snd . head) low <
snd a then (splitAt 10 . insertBy ((. snd) . flip compare . snd)
a) bs else ac
On Nov 7, 2007, at 9:06 AM, Bayley, Alistair wrote:
From: [EMAIL PROTECTED]
[mailto:[EMAIL PROTECTED] On Behalf Of manu
Haskell is conspicuously absent from the languages used to
tackle Tim
Bray's Wide Finder problem
(http://www.tbray.org/ongoing/When/200x/2007/10/30/WF-Results?
updated).
So far we have Ocaml, Erlang, Python, Ruby, etc...
Tim Bray mentions that GHC won't build on Solaris, so presumably
that
problem would need to be solved before Haskell appears in his
table. I
see that there are Solaris binary packages:
http://www.haskell.org/ghc/download_ghc_661.html#sparcsolaris
so perhaps he just needs to be pointed to them?
Alistair
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You didn't do a whole lot when I tried to run it. I know I am being
mean, but that seems to be what Tim Bray is doing. He takes code
and if it doesnt work, he isn't spending 3 weeks to figure it out.
So, I would just like to comment. I ran your code against an
access.log file and it gave me this:
[]
./a.out access.log
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