Looks like a flip-flop operator might work, for simple cases at least.

while (<DATA>){ 
   print if ( /def/ .. /end/ );
}


__DATA__
  puts "hai"
  def mult(a,b)
    a * b
  end
  puts "hello"
  def getCostAndMpg
    cost = 30000  # some fancy db calls go here
    mpg = 30
    return cost,mpg
  end
  AltimaCost, AltimaMpg = getCostAndMpg
  puts "AltimaCost = #{AltimaCost}, AltimaMpg = {AltimaMpg}"
[download]

yields:

  def mult(a,b)
    a * b
  end
  def getCostAndMpg
    cost = 30000  # some fancy db calls go here
    mpg = 30
    return cost,mpg
  end
[download]