Need help figuring out scala compiler errors.
- by klactose
Hello all,
I have been working on a project in scala, but I am getting some error messages that I don't quite understand. The classes that I am working with are relatively simple.
For example:
abstract class Shape
case class Point(x: Int, y: Int) extends Shape
case class Polygon(points: Point*) extends Shape
Now suppose that I create a Polygon:
val poly = new Polygon(new Point(2,5), new Point(7,0), new Point(3,1))
Then if I attempt to determine the location and size of the smallest possible rectangle that could contain the polygon, I get various errors that I don't quite understand.
Below are snippets of different attempts and the corresponding error messages that they produce.
val upperLeftX = poly.points.reduceLeft(Math.min(_.x, _.x))
Gives the error:
"missing parameter type for expanded function ((x$1) = x$1.x)"
val upperLeftX =
poly.points.reduceLeft((a: Point, b: Point) => (Math.min(a.x, b.x)))
Gives this error:
"type mismatch;
found : (Point, Point) = Int
required: (Any, Point) = Any"
I am very confused about both of these error messages. If anyone could explain more clearly what I am doing incorrectly, I would really appreciate it. Yes, I see that the second error says that I need type "Any" but I don't understand exactly how to implement a change that would work as I need it. Obviously simply changing "a: Point" to "a: Any" is not a viable solution, so what am I missing?
