# File lib/rake.rb, line 1843
1843:     def lookup(task_name, initial_scope=nil)
1844:       initial_scope ||= @scope
1845:       task_name = task_name.to_s
1846:       if task_name =~ /^rake:/
1847:         scopes = []
1848:         task_name = task_name.sub(/^rake:/, '')
1849:       elsif task_name =~ /^(\^+)/
1850:         scopes = initial_scope[0, initial_scope.size - $1.size]
1851:         task_name = task_name.sub(/^(\^+)/, '')
1852:       else
1853:         scopes = initial_scope
1854:       end
1855:       lookup_in_scope(task_name, scopes)
1856:     end