Hi everybody, I have written some code for several shapes, and i get a compiling error: parse error on input `:' though I can't find where the error is... data Shape = Ellipse Radius Radius | Polygon [Vertex] deriving Show type Radius = Float type Vertex = (Float, Float) area :: Shape -> Float area (Rectangle s1 s2) = s1 * s2 area (RtTriangle s1 s1) = s1 *s2 /2 area (Ellipse r1 r2) = pi * r1 * r2 area (Polygon(v1:v2:v3:vs)) = triArea v1 v2 v3 + area(Polygon(v1:v3:vs)) area(Polygon _ ) = 0 area (Polygon(v1:vs')) = polyArea vs where polyArea :: [Vertex] -> Float polyArea(v2:v3:vs') = triArea v1 v2 v3 + polyArea(v3:vs') polyArea _ = 0 triArea :: Vertex -> Vertex -> Vertex -> Float triArea v1 v2 v3 = let a = distBeetween v1 v2 b = distBeetween v2 v3 c = distBeetween v3 v1 s = 0.5 * (a + b + c) in sqrt (s * (s - a) * (s - b) * (s - c)) distBeetween :: Vertex -> Vertex -> Float distBeetween (x1, y1) (x2, y2) = sqrt ((x1 - x2) ^ 2 + (y1 - y2) ^ 2) Any suggestions? Thanks in advance, Skag55 _________________________________________________________________ On the road to retirement? Check out MSN Life Events for advice on how to get there! http://lifeevents.msn.com/category.aspx?cid=Retirement