/* 

  DCG in Picat v3.

  Some examples of DCG in Picat v3.

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

*/


import cp.
import v3_utils.

main => go.

%
% From https://www-users.cs.umn.edu/~gini/prolog/dcg.html
% """
% The argument Number is the number of the subject and main verb.
% It is instantiated to 'singular' or 'plural'.
% """
% sentence(plural,[men,hate,mice],[]).
% ?-sentence(_,[the,men,hate,mice],[]).
% ?-sentence(_,[the,mice,scare,the,man],[]).
go ?=>
  % sentence(X,Y,[]),
  phrase(sentence,X,Y),
  println([x=X,y=Y]),
  fail,
  nl.
  
go => true.

% "plural"
go2 ?=>
  % sentence(X,[men,hate,mice],[]),
  phrase(sentence,X,[men,hate,mice]),
  println(X),
  fail,
  nl.

go2 => true.

sentence(Number) --> noun_phrase(Number), verb_phrase(Number).
noun_phrase(Number) --> determiner(Number), noun(Number).
verb_phrase(Number) --> verb(Number), noun_phrase(_).

determiner(singular) --> [a].
determiner(_)        --> [the].
determiner(plural)   --> [].
noun(singular) --> [cat];[man];[mouse].
noun(plural)   --> [cats];[men];[mice].
verb(singular) --> [scares];[hates].
verb(plural)   --> [scare];[hate].


% From https://www-users.cs.umn.edu/~gini/prolog/dcg.html
go3 :-
  % sentence([the,cat,scares,the,mouse],[])
  % Note: If we don't restrict the length it's going infinite!
  member(Len,1..7),
  println(len=Len),
  bp.length(X,Len),
  sentence(X,[]),
  println(x=X),
  fail,
  nl.

go3.

sentence --> noun_phrase, verb_phrase.
noun_phrase --> determiner, noun.
verb_phrase --> verb, noun_phrase.
verb_phrase --> verb, sentence.

determiner --> [the].
determiner --> [a].
noun --> [cat].
noun --> [mouse].
verb --> [scares].
verb --> [hates].


% http://www.pathwayslms.com/swipltuts/dcg/
% """
% x = a book
% x = a car
% x = an book
% x = an car
% """
go4 :-
  % article_phrase(X,[]),
  phrase(article_phrase,X),
  println(x=X),
  fail.

go4.

article_phrase --> ("a" ; "an"),
	" ",
	noun2.

noun2 --> "book".
noun2 --> "car".


% https://www.metalevel.at/prolog/dcg
% Outputs:
%   bcad
go5 :-
   tree_nodes($node(a, node(b, nil,
                             node(c, nil, nil)),
                             node(d, nil, nil)),X,[]),
   println(X),
   fail,
   nl.

go5.

% Create a tree
% Outputs:
%   n = node(a,nil,node(b,nil,node(c,nil,node(d,nil,node(e,nil,nil)))))
%   x = abcde

go5b :-
   X = [a,b,c,d,e],
   % tree_nodes(N,X,[]),
   phrase(tree_nodes,N,X),
   println(n=N),
   println(x=X),
   nl.

go5b.


tree_nodes(nil) --> [].
tree_nodes(node(Name, Left, Right)) -->
        tree_nodes(Left),
        [Name],
        tree_nodes(Right).


% From https://www.metalevel.at/prolog/dcg
% Outputs: 5
go6 :-
   num_leaves($node(a,node(b,nil,nil),
                     node(c,nil,
                            node(d,nil,nil))), N),
   println(N),
   nl.

go6.

% Creates a tree of length 5.
%    t = node(_2610,nil,node(_2708,nil,node(_2800,nil,node(_28f8,nil,nil))))
go6b :-
   num_leaves(T, 5),
   println(t=T),
   nl.

go6b.

num_leaves(Tree, N) :-
        num_leaves_(Tree, 0, N).

num_leaves_(nil, N0, N) :- N #= N0 + 1.
num_leaves_(node(_,Left,Right), N0, N) :-
        num_leaves_(Left, N0, N1),
        num_leaves_(Right, N1, N).


% From https://www.metalevel.at/prolog/dcg
% I renamed list/1 to listx/1 to not conflict with Picat's built-in list/1.
% -> abcdef
go7 :-
   % concatenation([[a,b],[c,d],[e,f]], Ls,[]),
   phrase(concatenation,[[a,b],[c,d],[e,f]], Ls),   
   println(Ls),
   nl.
   
go7.

listx([])     --> [].
listx([L|Ls]) --> [L], listx(Ls).

concatenation([]) --> [].
concatenation([List|Lists]) -->
        listx(List),
        concatenation(Lists).



% https://www2.cs.arizona.edu/~collberg/Teaching/372/2005/Html/Html-27/index.html
go8 :-
  % s([john,kissed,lisa],[]),
  phrase(s,[john,kissed,lisa]),
  println(ok),
  % s(A,[]),
  phrase(s,A),
  println(A),
  fail,
  nl.

go8.

s --> np,vp.
vp --> v,np.
vp --> v.
np --> n.
n --> [john].
n --> [lisa].
n --> [house].
v --> [died].
v --> [kissed].

% https://www2.cs.arizona.edu/~collberg/Teaching/372/2005/Html/Html-27/index.html
% "Generating Parse Trees..."
% """
% s(np(n(john)),vp(v(died),np(n(john))))
% [john,dies,john]
% 
% s(np(n(john)),vp(v(died),np(n(lisa))))
% [john,dies,lisa]
% ...
% """
% 
go9 :-
  s(S,T,[]),
  println(S),
  println(T),
  nl,
  fail,
  nl.

go9.

% """
% s(np(n(john)),vp(v(kissed),np(n(lisa))))
% """
go9b :-
  s(S,[john,kissed,lisa],[]),
  println(S),
  fail,
  nl.

go9b.

% -> [john,kissed,lisa]
go9c :-
  s($s(np(n(john)),vp(v(kissed),
          np(n(lisa)))),S,[]),
  println(S),
  nl.
  
go9c.

s(s(NP,VP)) --> np(NP),vp(VP).
vp(vp(V,NP)) --> v(V), np(NP).
vp(vp(V)) --> v(V).
np(np(N)) --> n(N).
n(n(john)) --> [john].
n(n(lisa)) --> [lisa].
n(n(house)) --> [house].
v(v(died)) --> [dies].
v(v(kissed)) --> [kissed].