kestrels in rails

gistfile1.rb

# in Combinatory Logic, a Kestrel is a function that returns a constant function
# An example would be to have a return value and injecting some side effects before returning the value

def first_user_notified
  user = User.first
  user.send_email("foo")
  user
end
# => first user

# and now with a kestrel using "returning" - this is an example in rails
def first_user_notified
  returning User.first do |user|
    user.send_email
  end
end
# => first user

# ruby gives you tap on all objects, which is similar to the rails-specific "returning"
User.first.tap do |user|
  user.send_email
end
# => first user