# An tierator that filter its element by a predicate `pred`.
class FilterIter[E]
        super FunIter[E,nullable E]
        var pred: Fun1[E, Bool]

        redef init
        do
                if is_ok and not pred.call(my_iter.item) then next
        end

        redef fun item
        do
                assert is_ok
                return my_iter.item
        end

        redef fun next
        do
                loop
                        my_iter.next
                        if not is_ok then
                                break
                        end
                        var x = my_iter.item
                        if pred.call(x) then
                                break
                        end
                end
        end
end