Often, in games or UI, you might want to create a grid.

A custom iterators can provide such functionality.

class GridIterator {
  var gridWidth:Int = 0;
  var gridHeight:Int = 0;
  var i:Int = 0;

  public inline function new(gridWidth:Int, gridHeight:Int) {
    this.gridWidth = gridWidth;
    this.gridHeight = gridHeight;
  }

  public inline function hasNext() {
    return i < gridWidth * gridHeight;
  }

  public inline function next() {
    return new GridIteratorObject(i++, gridWidth);
  }
}

class GridIteratorObject {
  public var index(default, null):Int;
  public var x(default, null):Int;
  public var y(default, null):Int;

  public inline function new(index:Int, gridWidth:Int) {
    this.index = index;
    this.x = index % gridWidth;
    this.y = Std.int(index / gridWidth);
  }
}

Usage

The following example uses the GridIterator and displays a grid of 6x5 using dark colored divs. Because of the used js package/features, it only compiles in the JavaScript target.

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Grid Key value iterator

In Haxe 4, as alternative, you can also use a key value iterator.

class GridIterator {
  var gridWidth:Int = 0;
  var gridHeight:Int = 0;
  var i:Int = -1;

  public inline function new(gridWidth:Int, gridHeight:Int) {
    this.gridWidth = gridWidth;
    this.gridHeight = gridHeight;
  }

  public inline function hasNext() {
    return i < gridWidth * gridHeight;
  }

  public inline function next() {
    i++;
    return { key: i, value: { x: i % gridWidth, y: Std.int(i / gridWidth) } }
  }
}

Usage

for (idx => pos in new GridIterator(6, 5)) {
  trace(idx, pos.x, pos.y);
}

Learn more about iterators here: https://haxe.org/manual/lf-iterators.html