Question: Mapping two values to one value

[badBlackShark]

This is more a question whether a feature like this would even be feasible to implement. What I need is mapping two values to one value, here a basic example:

input = { first_name: 'Max', last_name: 'Mustermann' }

# Now we want to map the full name
# Option 1
map(:first_name, to: :full_name).then { value + values.get(:last_name) }

# Option 2
to(:full_name).then { "#{values.get(:first_name)} #{values.get(:last_name]}" }

What I would like to do is something like

map(:first_name, and: :last_name, to: :full_name).then { "#{value[0]} #{value[1]}" }
# or
map(:first_name, and: :last_name, to: :full_name).then { value.compact.join(' ') }

If one of the two doesn't exist, the mapper gets skipped, I would assume. If you use map? and one of them does not exist, then Undefined could be yielded (so if last_name does not exist, then value == ['Max', Undefined].

This and positional argument also takes a path, in case two different paths need to be walked:

input = { a: { b: 1 }, c: { d: 2 } }

map(:a, :b, and: [:c, :d], to: :e).then(&:sum) #=> { e: 3 }

I hope that's detailed enough :) Is it possible & feasible to implement a feature like this? Or would that mean basically having to rewrite everything?

Alternatively: Do you know of a better way of doing this, other than the two options I showed initially?