/* 

  Natural language: World of people, parks, trees, hats in Picat.

  From "Thinking as Computation", page 160ff

  This Picat model was created by Hakan Kjellerstrand, hakank@gmail.com
  See also my Picat page: http://www.hakank.org/picat/

*/


main => go.


go =>
  printit([a,big,tree]), % tree01
  printit([woman,beside,mary]), % linda
  printit([a,woman,beside,mary]), % linda
  printit([a,man,with,a,big,hat]), % george
  printit([the,hat,on,george]), % hat04
  % note: we have to use 'inx' instead of 'in'
  printit([a,man,inx,a,park,with,a,big,tree]), % <no solutio>
  printit([a,man,inx,a,park,with,a,small,tree]), % john, george
  printit([a,woman,inx,a,park,with,a,big,tree]), % mary ; linda
  printit([a,woman,inx,a,park,with,a,big,red,hat]), % linda
  printit([a,woman,beside,a,woman,with,a,blue,hat]), % mary ; linda
  printit([a,woman,with,a,blue,hat,beside,a,woman]), % mary
  printit([the,hat,on,a,small,woman,inx,a,park]), % 
  
  nl.



printit(P) => 
  println(P),
  All = findall(X, np(P,X)),
  println(All),

  nl.

person(john). 
person(george). 
person(mary). 
person(linda).

park(kew_beach). 
park(queens_park).

tree(tree01). 
tree(tree02). 
tree(tree03).

hat(hat01).
hat(hat02). 
hat(hat03). 
hat(hat04).

sex(john,male).
sex(george,male).
sex(mary,female).
sex(linda,female).

color(hat01,red).
color(hat02,blue).
color(hat03,red).
color(hat04,blue).

inx(john,kew_beach).
inx(george,kew_beach).
inx(linda,queens_park). 
inx(mary,queens_park).
inx(tree01,queens_park). 
inx(tree02,queens_park).
inx(tree03,kew_beach).

beside(mary,linda). 
beside(linda,mary).

on(hat01,john). 
on(hat02,mary). 
on(hat03,linda). 
on(hat04,george).

size(john,small).
size(mary,small).
size(george,big).
size(linda,small).
size(hat01,small).
size(hat02,small).
size(hat03,big).
size(hat04,big).
size(tree01,big).
size(tree02,small).
size(tree03,small).

% From page 161, "A lexicon in Prolog"
article(a).
article(the).

common_noun(park,X)  ?=> 
  park(X).
common_noun(tree,X)  ?=> 
  tree(X).
common_noun(hat,X)   ?=> 
  hat(X).
common_noun(man,X)   ?=> 
  person(X), 
  sex(X,male).
common_noun(woman,X) ?=>  
  person(X), 
  sex(X,female).

adjective(big,X)   ?=> 
  size(X,big).
adjective(small,X) ?=> 
  size(X,small).
adjective(red,X)   ?=> 
  color(X,red).
adjective(blue,X)  ?=> 
  color(X,blue).

preposition(on,X,Y)     ?=> 
  on(X,Y).
preposition(inx,X,Y)    ?=> 
  inx(X,Y). % Can't use 'in'!
preposition(beside,X,Y) ?=> 
  beside(X,Y).
% The preposition 'with' is flexible in how it is used.
preposition(with,X,Y)   ?=> 
  on(Y,X).     % Y can be on X
preposition(with,X,Y)   ?=> 
  inx(Y,X).    % Y can be in X
preposition(with,X,Y)   ?=> 
  beside(Y,X). % Y can be beside X


% Any word that is not in one of the four categories above.
proper_noun(X,X1) ?=> 
  X = X1,
  not article(X), not adjective(X,_),
  not common_noun(X,_), not preposition(X,_,_).



% From page 163 "A parser of noun phrases in Prolog"

np([Name],X) ?=> 
  proper_noun(Name,X).
np(ArtRest,X) ?=> 
  [Art|Rest] = ArtRest, 
  article(Art), 
  np2(Rest,X).
np(L,X) ?=> 
  np2(L,X).

np2(AdjRest,X) ?=> 
  AdjRest = [Adj|Rest],
  adjective(Adj,X), 
  np2(Rest,X).
np2(NounRest,X) ?=> 
  NounRest = [Noun|Rest], 
  common_noun(Noun,X), 
  mods(Rest,X).

mods([],_) ?=> 
  true.
mods(Words,X) ?=>
   append(Start,End,Words),
   pp(Start,X),
   mods(End,X).

% Break the words into two pieces.
% The first part is a PP.
% The last part is a Mods again.
pp(PrepRest,X) ?=> 
  PrepRest=[Prep|Rest],
  preposition(Prep,X,Y), 
  np(Rest,Y).