GHCi does things with optimisations off. Note the line on startup which says:
Compiling Main ( search.hs, interpreted )
You'll have better luck if you compile the code with optimisations and
keep the .o files around when running the program in ghci -- it will
notice the compiled copies and load those instead. You'll see
something like:
Skipping Main ( search.hs, search.o )
Also note that your 'infinite' function is in the prelude. It's called 'cycle'.
- Cale
On 08/12/05, Branimir Maksimovic
It seems that compiled programs run better then interactive ones. Following program with GHC works with pretty good performance in comparison to C++ one with similar but non recursive algorithm and beats it in memory consumtion. It only takes about 2mb of ram somehow when running compiled. I'm really amased. But in interactive mode both GHC and Hugs fail due heap exhaustion and running takes ages.Please can someone explain why? I intent to use only compiled Haskell anyway so GHC satisfies.
Greetings, Bane.
program performs search replace on a String
module Main where import IO main = do hSetBuffering stdout LineBuffering let sr = "search" rp = "replace" str= " able search sea baker search charlie \"" out = searchr sr rp (take (1000000*(length str)) $ infinite str) out1 = searchr sr rp (take (1000001*(length str)) $ infinite str) putStrLn $ "Working:" ++ sr ++ " " ++ rp ++ " " ++ str putStrLn $ (show (out == out1)) ++ "\n" ++ "\nDone\n" {- search replace " able search baker search charlie " -}
------------------------------------------------------------------------------- infinite xs = xs ++ infinite xs
searchr :: String->String->String -> String searchr [] _ xs = xs searchr _ [] xs = xs searchr _ _ [] = [] searchr sr rp xs | fst fnd = rp ++ searchr sr rp (snd $ snd fnd) | otherwise = (reverse $ fst $ snd fnd) ++ searchr sr rp (snd $ snd fnd) where fnd = searchr' sr xs ""
searchr' :: String->String->String -> (Bool,(String,String)) searchr' (sr:srs) xs fndSoFar = searchr'' (sr:srs) xs fndSoFar sr
searchr'' :: String->String->String->Char -> (Bool,(String,String)) searchr'' [] xs fnd _ = (True,(fnd,xs)) searchr'' _ [] fnd _ = (False,(fnd,[])) searchr'' (sr:srs) (x:xs) fndSoFar s | sr == x = searchr'' srs xs xxs s | otherwise = (False,searchr''' s xs xxs) -- (False,(xxs,xs)) where xxs = x:fndSoFar
searchr''' :: Char->String->String -> (String,String) searchr''' sr [] fndSoFar = (fndSoFar,[]) searchr''' sr (x:xs) fndSoFar | sr /= x = searchr''' sr xs (x:fndSoFar) | otherwise = (fndSoFar,x:xs) -------------------------------------------------------------------------------
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