alerting a non-string crashes OS X

[Edward Heil]

This isn't Perl, everything's not a string when you want it to be, so  
this isn't *necessarily* a bug, but crashing is no fun, so maybe the  
fact that it crashes instead of erroring out is a bug:

Shoes.app do
  button "click me" do
    alert 10
  end
end
On OS X, clicking the button crashes the app.