Well, perhaps you can help me figure out the problem with my exact program. Just in case it matters, the program draws a Mandelbox via volumetric ray casting. I can provide more information about the function, but I wouldn't think it's necessary, since my problem is with parsing. The error I'm getting is with the where-clause at the very bottom: traceRay (x,y) r@((cx,cy,cz):n) (vx,vy,vz) iter | m > 100 = do color $ Color3 (sin vx) (cos vy) (cos vz) vertex $ Vertex2 x y | otherwise = do [boxx,boxy,boxz] <- boxFold [vx,vy,vz] (ballx,bally,ballz) <- ballFold (boxx,boxy,boxz) traceRay (x, y) r (2*ballx + cx, 2*bally + cy, 2*ballz + cz) (iter-1) where boxFold [] = return [] boxFold (a:b) | a > 2 = do rem <- boxFold b return $ (2-a):rem | a < (-2) = do rem <- boxFold b return $ (-2-a):rem |otherwise = do rem <- boxFold b return $ (a):rem ballFold (x,y,z) | n < 0.5 = return (4*x, 4*y, 4*z) | n < 1 = return (x/(n*n), y/(n*n), z/(n*n)) | otherwise = return (x, y, z) where n = sqrt $ x*x + y*y + z*z where m = sqrt $ vx*vx + vy*vy + vz*vz On 7/21/2010 3:13 AM, Nicolas Wu wrote:
There's nothing wrong with the use of your example, I'm guessing it's something in your ... that's leading to the parse error. This compiles just fine:
f a b | c> 1 = 1 | c< 1 = 2 | otherwise = 3 where c = a+b
Nick