Invercargill/src/lib/Generators/Range.vala

namespace Invercargill.Generators {

    internal class Range : Enumerable<int> {

        private int start;
        private int stride;
        private int stop;

        public Range(int initial, int end, int stride) {
            start = initial;
            stop = end;
            this.stride = stride;
        }

        public override int? peek_count() {
            return (stop - start) / stride;
        }

        public override EnumerableInfo get_info() {
            return new EnumerableInfo.infer_ultimate (this, EnumerableCategory.COMPUTED);
        }

        public override Tracker<int> get_tracker() {
            var i = start;

            return new LambdaTracker<int>(
                () => i < stop,
                () => {
                    var val = i;
                    i += stride;
                    return val;
                });
        }

    }

}