# File lib/rake.rb, line 84
84:     def ext(newext='')
85:       return self.dup if ['.', '..'].include? self
86:       if newext != ''
87:         newext = (newext =~ /^\./) ? newext : ("." + newext)
88:       end
89:       self.chomp(File.extname(self)) << newext
90:     end