goto.rb

require 'continuation'

$__labels__ = {}

def label(label)
  callcc {|cc| $__labels__[label] = cc }
end

def goto(label)
  $__labels__[label].call
end

def a
  label :c
  puts 'i call b'
  b
end

def b
  puts 'i goto c'
  goto :c
end

a