TCSH tab auto complete with the part of current typed command

I am trying to write my own complete for a command. The completion needs to use a portion of the typed command to for a path search. I am trying to get the following behavior When I write my_commad -ws my_ws -t[TAB] a list of folders under my_ws/tests appears as a list of completion I couldn't figure out how to break it I tried the following, but failed because of quotes problem, I guess

complete my_command 'n@-t@echo $COMMAND_LINE | perl -ne '/-ws (\w+)/; print $1'@'