% File: c.p
%       grammar for a shapes micro-world
%       pseudo-code for semantic action translated to Prolog

:- ['process.p'].
:- dynamic shape/4.

sentence -->  cmmnd.
sentence -->  query.
sentence -->  [].

cmmnd -->  [place], indefArticle, color(C), [square], [at],
          number(X), number(Y), [with], [side], number(S), ['.'],
          {
          assert(shape(square,coords(X, Y),side(S),color(C)))
          }.

cmmnd --> [place], indefArticle, color(C), [rectangle], [at],
          number(X), number(Y),
          [of], [height], number(H), [and], [width], number(W), ['.'],
          {
          assert(shape(rectangle,coords(X, Y),sides(H,W),color(C)))
          }.

cmmnd --> [place], indefArticle, color(C), [circle], [at],
          number(X), number(Y), [of], [radius], number(R), ['.'],
          {
          assert(shape(circle,coords(X, Y),radius(R),color(C)))
          }.

cmmnd -->  [stop], ['.'].

query --> [what], shapes(Shape), [are], [there], ['?'],
          {
          enumerate(Shape)
          }.

query --> [what], [color], shapes(Shape), [are], [present], ['?'],
          {
          enumerate_colors(Shape)
          }.

query --> [are], [there], [any], color(C), shapes(Shape), [present], ['?'],
          {
          respond_yes_no(C,Shape)
          }.

query --> [how], [big], [is], defArticle, shape(Shape), [at],
          number(X), number(Y), ['?'],
          {
          respond_size(Shape,X,Y)
          }.

defArticle --> [the].

indefArticle --> [a].
indefArticle --> [an].

color(red) --> [red].
color(blue) --> [blue].
color(green) --> [green].

number(N) --> [N], { number(N) }.

shape(square) --> [square].
shape(rectangle) --> [rectangle].
shape(circle) --> [circle].
shape(shape) --> [shape].

shapes(square) --> [squares].
shapes(rectangle) --> [rectangles].
shapes(circle) --> [circles].
shapes(shape) --> [shapes].

enumerate(shape) :-
   shape(Shape,coords(X,Y),_,color(C)),
   write(Shape),
   write_string(" at ("), write(X), write_string(","),
   write(Y), write_string("), with color "),
   write(C), nl,
   fail.
enumerate(shape).

enumerate(Shape) :-
   shape(Shape,coords(X,Y),_,color(C)),
   write(Shape),
   write_string(" at ("), write(X), write_string(","),
   write(Y), write_string("), with color "),
   write(C), nl,
   fail.
enumerate(_).

enumerate_colors(shape) :-
   shape(_,coords(_,_),_,color(C)),
   write(C), nl,
   fail.
enumerate_colors(shape).

enumerate_colors(Shape) :-
   shape(Shape,coords(_,_),_,color(C)),
   write(C), nl,
   fail.
enumerate_colors(_).

respond_yes_no(C,shape) :-
   shape(_,coords(_,_),_,color(C)),
   write_string("yes"), nl.
respond_yes_no(_,shape) :-
   write_string("no"), nl.

respond_yes_no(C,Shape) :-
   shape(Shape,coords(_,_),_,color(C)),
   write_string("yes"), nl.
respond_yes_no(_,_) :-
   write_string("no"), nl.

respond_size(shape,X,Y) :-
   shape(_,coords(X,Y),Size,color(_)),
   write(Size), nl.
respond_size(_,X,Y) :-
   write_string("Couldn't find anything at "),
   write(X), write_string(" "), write(Y), nl.

respond_size(Shape,X,Y) :-
   shape(Shape,coords(X,Y),Size,color(_)),
   write(Size), nl.
respond_size(_,X,Y) :-
   write_string("Couldn't find anything at "),
   write(X), write_string(" "), write(Y), nl.