thinking.rb

# file1

namespace Yehuda

class String
  def printout
    puts self
  end
end

# file1 after recompilation

class String
  define_method("__ns__::Yehuda::printout") do
    puts self
  end
end

# file2

namespace Rails

class String
  def printout
    puts "Rails: #{self}"
  end
end

# file2 after recompilation

class String
  define_method("__ns__::Rails::printout") do
    puts "Rails: #{self}"
  end
end

# file3

use Yehuda
use Rails

"Yehuda".printout

# file2 after recompilation

tmp = "Yehuda"
if meth = callsite.get(String, :printout)
  tmp.send(meth)
end

if tmp.respond_to?("__ns__::Yehuda::printout")
  callsite.set(String, :printout, "__ns__::Yehuda::printout")
  tmp.send("__ns__::Yehuda::printout")
elsif tmp.respond_to?("__ns__::Rails::printout")
  callsite.set(String, :printout, "__ns__::Rails::printout")
  tmp.send("__ns__::Rails::printout")
else
  callsite.set(String, :printout, "printout")
  tmp.printout
end