Hello, Isaac, this works for me. Thx a lot, Steffen 2007/12/5, Isaac Dupree :

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Hi,

Stefan and Isaac, thx for providing quick advice.

@Stefan: Unfortunately I have to use a list. @Isaac: I do not get it. Could you please provide a short example of your approach?

The question still remains. Which arguments do I have ghc to start with to get the same behavior than hugs with -98 +o (here it works).

I provide my example for testing purposes:

module Test where import Test.QuickCheck import Monad(liftM,liftM2)

type Program = [Stmt] data Stmt = Text | IfElse Program Program | While Program deriving (Eq, Show)

instance Arbitrary [Stmt] where arbitrary = sized genProg instance Arbitrary Stmt where arbitrary = sized genStmt

genStmt::Int->Gen Stmt genStmt 0 = return Text genStmt 1 = return Text genStmt 2 = oneof [return Text, return (While [Text])] genStmt n | n>2 = oneof ([return Text, liftM While (genProg (n-1))]++ [liftM2 IfElse (genProg k) (genProg (n-k-1))|k<-[1..n-2]])

genProg::Int->Gen Program genProg 0 = return [] genProg 1 = return [Text] genProg n | n>1 = oneof ((liftM (\x->[x]) (genStmt n)):[liftM2 (:) (genStmt k) (genProg (n-k))|k<-[1..n-1]])

prop_ConstructParse progr = True where types = progr::Program

main = mapM_ (\(s,a) -> putStrLn s >> a) [("flowchart construct and

Steffen Mazanek wrote: parse",

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test prop_ConstructParse)]

is prop_ConstructParse the only thing that breaks when you remove the instance Arbitrary [Stmt] where arbitrary = sized genProg, or have I missed something? If that's all, try this (untested) :

prop_ConstructParse = forAll (sized genProg) (\progr -> True)

and similarly for other properties.

Or, you _can_ use a newtype for quickcheck-only, something like this:

newtype P = P { unP :: Program } instance Show P where show = show . unP instance Arbitrary P where arbitrary = sized genProg . unP prop_ConstructParse (P progr) = True

Isaac

-- Dipl.-Inform. Steffen Mazanek Institut für Softwaretechnologie Fakultät Informatik Universität der Bundeswehr München 85577 Neubiberg Tel: +49 (0)89 6004-2505 Fax: +49 (0)89 6004-4447 E-Mail: steffen.mazanek@unibw.de