a prototype of an inerface to convert object to hash

ohashi.rb

def hash_from(obj, keys, options={})
  keys.inject({}) do |h, key|
    v = obj.send(key)
    h[key] = v unless options[:ignore_nil] && v.nil?
    h
  end
end

klass = Struct.new(:a, :b, :c)

obj1 = klass.new(1, 2, 3)

puts hash_from(obj1, %i[a b])
puts hash_from(obj1, %i[a b c])

obj2 = klass.new(1, 2)
puts hash_from(obj2, %i[a b c])
puts hash_from(obj2, %i[a b c], { ignore_nil: true })