imgoingtohellforthis.rb

class Context
  def initialize
    @magic = {}
    @lines = IO.readlines(__FILE__)
  end

  def method_missing *args
    @magic[@lines[caller_locations[0].lineno - 1][/\s*(\S+)\s*=/, 1]] = args
  end
end

def Foo
  ctx = Context.new
  ctx.instance_eval(&proc)
  p ctx.instance_variable_get(:@magic)
end

Foo do
  foo = some :thing
  bar = other 1, 2
end