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@UnkindPartition
Created January 11, 2017 09:49
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forM_ memory test
for n in 5000 50000 500000 5000000; do
for impl in roman michael base; do
printf "%7d %10s" $n $impl
./test4 $impl $n +RTS -s 2>&1|perl -lne '/(^.*bytes).*residency/&&print $1'
done
done
import Control.Monad
import Data.Foldable
import System.Environment
forM_1 :: (Monad m, Traversable t) => t a -> (a -> m ()) -> m ()
forM_1 a f =
let l = toList a
b = (False <$ tail l) ++ [True]
in
foldr (\(x,b) r -> if b then f x else f x >> r)
(return ()) (zip l b)
forM_2 :: (Applicative m, Foldable f) => f a -> (a -> m r) -> m ()
forM_2 a f =
go (toList a)
where
go [] = pure ()
go [x] = () <$ f x -- here's the magic
go (x:xs) = f x *> go xs
uncons :: [a] -> Maybe (a, [a])
uncons [] = Nothing
uncons (x:xs) = Just (x, xs)
printChars idx str impl = impl (uncons str) $ \(c, str') -> do
when (idx `mod` 100000 == 0)
$ putStrLn $ "Character #" ++ show idx ++ ": " ++ show c
printChars (idx + 1) str' impl
main :: IO ()
main = do
args <- getArgs
let
impl :: Maybe a -> (a -> IO ()) -> IO ()
impl =
case args !! 0 of
"base" -> forM_
"roman" -> forM_1
"michael" -> forM_2
n = read $ args !! 1
printChars 1 (replicate n 'x') impl
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