Rubyists: What is this called?

Question

Say I have a pool of enumerables that I want to group by an attribute:

cars = Car.all.group_by(&:color)

Then I want to iterate over those cars like so:

cars.inject([]) do |stack, (color, cars)|
  stack << cars.each do |car|
   ...
  end
end

What is the term for the block variable extension (between the parentheses)?

Answer 1

I call it destructuring bind or destructuring assignment, that's what it's usually called in other programming languages. In Ruby, it's often called multiple assignment or parallel assignment. If you want to know what it's "officially" called, you could look it up in the Draft ISO Specification.