yes/no

gistfile1.rb

ruby-1.9.2-p290 :001 > class Object
ruby-1.9.2-p290 :002?>     def yes
ruby-1.9.2-p290 :003?>         true
ruby-1.9.2-p290 :004?>       end
ruby-1.9.2-p290 :005?>     
ruby-1.9.2-p290 :006 >       def no
ruby-1.9.2-p290 :007?>         false
ruby-1.9.2-p290 :008?>       end
ruby-1.9.2-p290 :009?>   end
 => nil 
ruby-1.9.2-p290 :010 > puts "hello" if yes
hello
 => nil 
ruby-1.9.2-p290 :011 > puts "hello" if no
 => nil