% Partial execution of program progpextddf.pl
% progpextddf1.pl  

td_parse(np, [toby | Words], Words).
td_parse(np, [scotch | Words], Words).
td_parse(np, [drinks | Words], Words).
td_parse(v, [drinks | Words], Words).

td_parse(s, Input, ResultInput):- 
       td_parse(np, Input, RemainingInput),
       td_parse(vp, RemainingInput, ResultInput).
td_parse(vp, Input, ResultInput):- 
       td_parse(v, Input, ResultInput).
td_parse(vp, Input, ResultInput):- 
       td_parse(v, Input, RemainingInput),
       td_parse(np, RemainingInput, ResultInput).