flat_scope.rb

# =================
# Spell: Flat Scope
# =================

# Use a closure to share variables between two scopes.

class C
  def an_attribute
    @attr
  end
end

obj = C.new
a_variable = 100

# flat scope:
obj.instance_eval do
  @attr = a_variable
end

obj.an_attribute # => 100

# For more information: http://www.pragprog.com/titles/ppmetr/metaprogramming-ruby