:- tree_extensions.
:- multifile if/2.

% poradi atributu na vystupu
phon <<< dtrs.

% slovnik
pepa ~~> (word,cat:noun).
pase ~~> (word,cat:verb).

% pravidla
nv ## 
   phrase 
===> 
    cat> (word,cat:noun),
    cat> (word,cat:verb).