Does Malcolm's Binary library exist for ghc? If not, is there a standard way (ie using Haskell that works on any compiler) to dump a data structure into a file that another program or part of the same program can then pick up and read (cf "serialize" in Java)? I'm reluctant to go with a solution that's compiler-specific.
Using Show & Read is the only really portable way to do this, unfortunately. [snip]
Well, it's not really portable... Try the program at the end of this file, by first executing hugsMain in hugs, exiting and then running main in ghc or ghci, and you'll see: | Cons{hd='a',tl=(Cons{hd='b',tl=Nil})} | *** Exception: Prelude.read: no parse So, at least ghc and hugs disagree... My ghc version is 5.02 and my hugs is February 2000/2001 (both give the same output). Cheers, Jan de Wit ----8<---- module Test where data List a = Nil | Cons { hd :: a, tl :: List a } deriving (Show,Read,Eq) theList = Cons 'a' (Cons 'b' Nil) hugsMain = do writeFile "test.txt" (show theList) main main = do s <- readFile "test.txt" let theListFromFile = read s print theList print theListFromFile print $ theList == theListFromFile writeFile "test.txt" (show theList)