% file: sr.p
% desc: simplification rules for "geometric answer-man" language

% -----------------------------------------------------------
% see allowable sentences in file "source-lang"

% ===========================================================
% simplification rules

% -----------------------------------------------------------
% sr(+S,-T)

sr([pick, up |X],[pick | X]).
sr([put, down |X],[put | X]).
sr([how, many, surfaces, are, on |X],[what, number, surfaces | X]).

sr([the | X],X).

% these rules reduce the input to:

%    pick Color Shape
%    put Color Shape
%    what number surfaces Color Shape

% -----------------------------------------------------------
% simplify(+S,-T)

simplify(X,Z) :-
   sr(X,Y),
   !,
   simplify(Y,Z).

simplify([X|Xs],[X|Zs]) :-
   simplify(Xs,Zs).

simplify([],[]).