godef.rb

def godef(inputs, returns, &func)
  Proc.new do | *args |
    obj = Object.new
    inputs.map.with_index{|v, i| obj.instance_variable_set(v, args[i])} 
    returns.map{|v| obj.instance_variable_set(v, nil) } 
    obj.instance_eval(&func)
    returns.map{|v| obj.instance_variable_get(v) } 
  end
end

my_awesome_method = godef [:@n, :@p], [:@hoge,:@moge]  do
  @hoge = @n * 10
  @moge = @p * 100
end
p my_awesome_method.call(2, 4)