% file:  grammar-a.p
%        recognizer for X-bar verb phrases
%        - elimination of left recursion

% ---------- base productions ----------

sentence --> np, vp, ['.'].
sentence --> [].

% np --> def_article, adj_list, noun.
np --> [she].
np --> [the], [space], [shuttle].

vp --> vbar.


% elimination of left-recursion
% vbar --> verb, vcomp.
% vbar --> vbar, vcomp.
vbar --> verb, vcomp.
vbar --> verb, vcomp, lvbar.

lvbar --> vcomp.
lvbar --> vcomp, lvbar.

vcomp --> np.
vcomp --> pp.
vcomp --> [].

pp --> [at], [the], [airfield].
pp --> [on], [a], [friday].

verb --> [landed].