lookup (Rake::TaskManager)

          # File lib/rake.rb, line 1509
    1509:     def lookup(task_name, initial_scope=nil)
    1510:       initial_scope ||= @scope
    1511:       task_name = task_name.to_s
    1512:       if task_name =~ /^rake:/
    1513:         scopes = []
    1514:         task_name = task_name.sub(/^rake:/, '')
    1515:       elsif task_name =~ /^(\^^+)/
    1516:         scopes = initial_scope[0, initial_scope.size - $1.size]
    1517:         task_name = task_name.sub(/^(\^^+)/, '')
    1518:       else
    1519:         scopes = initial_scope
    1520:       end
    1521:       lookup_in_scope(task_name, scopes)
    1522:     end