=begin
Ruby provides a number of hooks that allow a developer
to change the behavior of objects.
The design is similar to JavaScript's Proxies (both are
metaobject protocols), but unlike proxies,
these hooks apply for all objects.

The most famous of these is method_missing,
based on Smalltalk's doesNotUnderstand:.
=end

# Consider Ruby on Rails.
# With Rails you refer to a record's fields by their names.
# We will (crudely) simulate that.
class Record
  def initialize fields
    @fields = fields
  end

  def method_missing m, *args
    meth_name = m.to_s
    if (meth_name.end_with?("=")) then
      @fields[meth_name.chop] = args[0]
    else
      @fields[meth_name]
    end
  end
end

r = Record.new ({ 'fname' => 'Rick', 'lname' => 'Grimes', 'profession' => 'Police Officer' })
puts r.profession
r.profession = 'Zombie hunter'
puts r.profession

# Ruby has const_missing as well, which works in a similar manner, except that it applies
# to missing class constants