# File lib/rake/task_manager.rb, line 156
156:     def lookup(task_name, initial_scope=nil)
157:       initial_scope ||= @scope
158:       task_name = task_name.to_s
159:       if task_name =~ /^rake:/
160:         scopes = []
161:         task_name = task_name.sub(/^rake:/, '')
162:       elsif task_name =~ /^(\^+)/
163:         scopes = initial_scope[0, initial_scope.size - $1.size]
164:         task_name = task_name.sub(/^(\^+)/, '')
165:       else
166:         scopes = initial_scope
167:       end
168:       lookup_in_scope(task_name, scopes)
169:     end