It may be somewhat awkward; zipping collections to iterate over them in unison makes the first one (the sender) seem special, while it not necessarily is. And accumulating more than one value isn't always straightforward; you usually have to reduce explicitly. But it's so much better in the general case!
Like the example you showcase your macro with. In Ruby it would be:
lst = [[1, 2], :dud, [3, 4], [5, 6]]
lst.grep(Array).flatten.sum
=> 21
You can see what it does at a glance, you don't have to immerse yourself inside the directives to follow the logic. And when you can't do that, declaring iterators and accumulators outside a loop and then iterating and accumulating "by hand" yields code not so different than your more complex examples.
def partition (arr)
yes = []
no = []
arr.each do |elt|
if yield elt
yes << elt
else
no << elt
end
end
[yes, no]
end
Like the example you showcase your macro with. In Ruby it would be:
You can see what it does at a glance, you don't have to immerse yourself inside the directives to follow the logic. And when you can't do that, declaring iterators and accumulators outside a loop and then iterating and accumulating "by hand" yields code not so different than your more complex examples.