[Haskell-cafe] Re: Why so slow?
Lyle Kopnicky wrote: The code below is using way more RAM than it should. It seems to only take so long when I build the 'programs' list - the actual reading/parsing is fast. For a 5MB input file, it's using 50MB of RAM! Any idea how to combat this? (ethereal voice) ... Children of Amaunator ... heed my words ... in no long, the world ... will perish, will ... crumble under the blackened forces of IO ... but there is ... hope ... i can feel that ... ensure :: (a - Bool) - String - a - a ensure b s x = if b x then x else error s ... or switching to ... monadic parser combinators ... like Text.ParserCombinators.Parsec ... can hold strong the light for ... another aeon or two ... Regards, afpelmus ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] Re: Why so slow?
Lyle Kopnicky wrote: The code below is using way more RAM than it should. It seems to only take so long when I build the 'programs' list - the actual reading/parsing is fast. For a 5MB input file, it's using 50MB of RAM! Any idea how to combat this? 1) I strongly recommend to work through at least the relevant parts of the tutorial 'Write yourself a scheme in 48 hours' (google for the title). It explains how to use efficient parser combinator libraries, how to cleanly separate IO from pure computations, how to use Error monad (instead of IO) to recover from errors, etc. pp. 2) Use String or ByteString.Lazy together with readFile to read the input on demand. Else your program must suck all of the input into memory before processing can even start. (This works whenever processing of the input stream is more or less sequential). HTH Ben ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
