Hash#multi_fetch - Fetch multiple keys from a Hash and support default values when a key is missing.

multi_fetch.rb

# Usage:
#
# h = { a: 1, b: 2 }
#
# h.multi_fetch(:a)         # => [1]
# h.multi_fetch(:a, :b)     # => [1, 2]
# h.multi_fetch(:a, :c)     # => [1, nil]
# h.multi_fetch(a: 1, c: 3) # => [1, 3]

class Hash
  def multi_fetch(*many)
    if many.size == 1 and (defaults = many.first).is_a?(Hash)
      reverse_merge(defaults).values_at(*defaults.keys)
    else
      values_at(*many)
    end
  end
end