How to implement Iterable<E>

Question

I am trying to port the Java code below to Dart and am puzzled about to do this.

In Java the Iterable interface is where clean with one method and to implement this is a snap.

How is this code best transformed to Dart?

/**
 * Chess squares represented as a bitmap.
 */
public class ChessSquares implements Iterable<ChessSquare> {

private static class ChessSquaresIterator implements Iterator<ChessSquare> {
    long bits;
    int nextBit;

    public ChessSquaresIterator(long bits) {
        this.bits = bits;
        nextBit = Long.numberOfTrailingZeros(bits);
    }

    @Override
    public boolean hasNext() {
        return (nextBit < 64);
    }

    @Override
    public ChessSquare next() {
        ChessSquare sq = ChessSquare.values()[nextBit];
        bits = bits & ~sq.bit;
        nextBit = Long.numberOfTrailingZeros(bits);
        return sq;
    }

    @Override
    public void remove() {
        throw new UnsupportedOperationException();
    }
}


@Override
public Iterator<ChessSquare> iterator() {
    return new ChessSquaresIterator(bits);
}

...

Answer 1

By using IterableMixin you only need to implement the iterator-function.

class ChessSquares with IterableMixin<ChessSquare> {
    @override
    Iterator<ChessSquare> get iterator => new ChessSquaresIterator(bits);
    ...
}

Visit http://blog.sethladd.com/2013/03/first-look-at-dart-mixins.html for a short introduction on mixins.

The Iterator-interface is straight forward. You only have to implement the function moveNext and the getter current.