A question about region, rail, array and point and the differences between X10 and Java

[Yoav Zibin]

I saw your email to Martha, and I understand you don't know Java, so I'll try to explain it but you might need to do more reading to understand the concept of objects (as found in Java).

yes, points in X10 are not like arrays in C++.
Arrays in C++ are simply pointers.
Point in X10 is an Object, and you can see the fields and methods it has in Point.x10 :
public final class Point(rank:Int) implements (Int) => Int, Ordered[Point(rank)] {
  ...
  def this(coords:Array[int](1)):Point(coords.size) {
        property(coords.size);
        ...
  }
  ...
}

so a point is very similar to
Array[Int](1)
(a 1-dimensional array of Int elements).


I agree that it is confusing that we have:
region, rail, array and point

Rail is 1-dimensional 0-based array  (so you can access it with an Int index).
Array can be multi-dimensional (and you access them using a point as an index).
Region is a set of points.

You can find a lot of tutorials here:
http://x10.codehaus.org/Tutorials

Try to learn Java as best as you can, because it will help a lot with X10.
A lot of the concepts in X10 are very similar to Java, like:
inheritance (extends and implements),
interfaces,
generics,
final fields and locals,
objects, methods, for loops, etc

But X10 has some special classes (like Array, Point, Region, etc)
and some new concepts (like closures, and concurrency constructs).

Cheers,
Yoav