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PONeed help figuring out scala compiler errors
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2010-05-20T05:55:21.757
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Body
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: <pre><code>abstract class Shape case class Point(x: Int, y: Int) extends Shape case class Polygon(points: Point*) extends Shape </code></pre> Now suppose that I create a Polygon: <pre><code>val poly = new Polygon(new Point(2,5), new Point(7,0), new Point(3,1)) </code></pre> 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. <pre><code>val upperLeftX = poly.points.reduceLeft(Math.min(_.x, _.x)) </code></pre> Gives the error: "missing parameter type for expanded function ((x$1) => x$1.x)" <pre><code>val upperLeftX = poly.points.reduceLeft((a: Point, b: Point) => (Math.min(a.x, b.x))) </code></pre> 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? 
Tags
<scala><compiler-errors><reduce>
Title
Need help figuring out scala compiler errors
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