Another stellar realization from Mauricio:

 iptocountry = Hash.new do |h,ip|
   h[ip] = `geoiplookup #{ip}`.chomp.gsub(/^GeoIP Country Edition: /,"")
 end
 iptocountry.update Marshal.load(File.read("geo.cache")) rescue nil

Want to know what it does?

Continue to full post. (216 words)

Koichi Sasada says if you can predict the correct output of the following, you are a great Ruby hacker. Man, that’s true!

 Const = :top
 class C
   Const = :C
 end

 C.instance_eval %{p Const}
 C.instance_eval  {p Const}
 C.module_eval   %{p Const}
 C.module_eval    {p Const}
 C.class_eval    %{p Const}
 C.class_eval     {p Const}
 eval            %{p Const}
 eval             {p Const}

Even if you don’t get the answers right, I will call you a great Ruby hacker if you can explain it. (As usual: ~sasada.)