Nice methods. I think we should revisit the idea of wrapping the scalars/arrays in objects.

I think we should revisit the idea of wrapping the scalars/arrays in objects.

That makes very little sense if not supported by language. Wait for PHP 7.

Now it (i.e. map of filter) can be implemented using generators:

class Iterators
{
    public static function map($iterator, callable $callback)
    {
        foreach ($iterator as $key => $value) {
            yield $key => $callback($value);
        }
    }

    public static function filter($iterator, callable $callback)
    {
        foreach ($iterator as $key => $value) {
            if ($callback($value)) {
                yield $key => $value;
            }
        }
    }

Yes. But I would expect map to return array if I pass array as argument. Using generators when Traversable is passed should be OK.

@dg Generators are good but I don't think we need functions like this in Nette. Just use nikic/iter.