/**
         
 * Warranty & Liability
         
 * To the extent permitted by applicable law and unless explicitly
         
 * otherwise agreed upon, XLOG Technologies AG makes no warranties
         
 * regarding the provided information. XLOG Technologies AG assumes
         
 * no liability that any problems might be solved with the information
         
 * provided by XLOG Technologies AG.
         
 *
         
 * Rights & License
         
 * All industrial property rights regarding the information - copyright
         
 * and patent rights in particular - are the sole property of XLOG
         
 * Technologies AG. If the company was not the originator of some
         
 * excerpts, XLOG Technologies AG has at least obtained the right to
         
 * reproduce, change and translate the information.
         
 *
         
 * Reproduction is restricted to the whole unaltered document. Reproduction
         
 * of the information is only allowed for non-commercial uses. Selling,
         
 * giving away or letting of the execution of the library is prohibited.
         
 * The library can be distributed as part of your applications and libraries
         
 * for execution provided this comment remains unchanged.
         
 *
         
 * Restrictions
         
 * Only to be distributed with programs that add significant and primary
         
 * functionality to the library. Not to be distributed with additional
         
 * software intended to replace any components of the library.
         
 *
         
 * Trademarks
         
 * Jekejeke is a registered trademark of XLOG Technologies AG.
         
 */
         

         
/**
         
 * Source of test cases are the following standards and proposals:
         
 *   - Definite Clause Grammar Rules, ISO/IEC DTR 13211–3:2006
         
 *     <a href="https://www.complang.tuwien.ac.at/ulrich/iso-prolog/dcgs/dcgsdin140720.pdf">www.complang.tuwien.ac.at/ulrich/iso-prolog/dcgs/dcgsdin140720.pdf</a>
         
 */
         

         
runner_file(stream, dcg, 'XLOG 4.1 dcg').
         

         
/****************************************************************/
         
/* Term Expansion                                               */
         
/****************************************************************/
         

         
/* X --> Y */
         

         
runner_pred(-->, 2, stream, dcg, 'XLOG 4.1.3').
         
runner_case(-->, 2, stream, dcg, 'XLOG 4.1.3, XLOG 1') :-
         
   expand_term((p --> q), X),
         
   X = (p(A, B) :- q(C, D)),
         
   C == A, D == B.
         
runner_case(-->, 2, stream, dcg, 'XLOG 4.1.3, XLOG 2') :-
         
   expand_term((p, q --> r), X),
         
   X = (p(A, B) :- r(C, D), q(E, F)),
         
   C == A, F == D, E == B.
         
runner_case(-->, 2, stream, dcg, 'XLOG 4.1.3, XLOG 3') :-
         
   expand_term((p; q --> r), X),
         
   X = (p(A, B); q(C, D) :- r(E, F)),
         
   C == A, D == B, E == A, F == B.
         
runner_case(-->, 2, stream, dcg, 'XLOG 4.1.3, XLOG 4') :-
         
   expand_term((p --> [a], !, [b]), X),
         
   X = (p([a|A], B) :- true, !, C = [b|D]),
         
   C == A, D == B.
         
runner_case(-->, 2, stream, dcg, 'XLOG 4.1.3, XLOG 5') :-
         
   catch(expand_term((_ --> q), _), error(E,_), true),
         
   E == instantiation_error.
         
runner_case(-->, 2, stream, dcg, 'XLOG 4.1.3, XLOG 6') :-
         
   catch(expand_term((p, [a|_] --> q), _), error(E,_), true),
         
   E == instantiation_error.
         
runner_case(-->, 2, stream, dcg, 'XLOG 4.1.3, XLOG 7') :-
         
   catch(expand_term((p --> [a|b], q), _), error(E,_), true),
         
   E == type_error(list, b).
         
runner_case(-->, 2, stream, dcg, 'XLOG 4.1.3, XLOG 8') :-
         
   catch(expand_term((p --> 1), _), error(E,_), true),
         
   E == type_error(callable, 1).
         

         
/****************************************************************/
         
/* Phrase Expansion                                             */
         
/****************************************************************/
         

         
/* phrase(X, Y, Z) */
         

         
test1 --> test4, test5.
         
test2 --> test4; test5.
         
test3a(X) --> (test3b(X) -> test4; test5).
         
test3b(1) --> [].
         
test4 --> "foo".
         
test5 --> "bar".
         
test6(X) --> test3b(X), !, test4.
         
test6(_) --> test5.
         
test7(X) --> {X=1}, !, test4.
         
test7(_) --> test5.
         
test8 --> test4, \+ test5.
         

         
runner_pred(phrase, 3, stream, dcg, 'XLOG 4.1.4').
         
runner_case(phrase, 3, stream, dcg, 'XLOG 4.1.4, XLOG 1') :-
         
   test1("foobarbaz", X), X == "baz".
         
runner_case(phrase, 3, stream, dcg, 'XLOG 4.1.4, XLOG 2') :-
         
   test2("barbaz", X), X == "baz".
         
runner_case(phrase, 3, stream, dcg, 'XLOG 4.1.4, XLOG 3') :-
         
   test3a(2, X, ""), X == "bar".
         
runner_case(phrase, 3, stream, dcg, 'XLOG 4.1.4, XLOG 4') :-
         
   \+ test4("baz", "").
         
runner_case(phrase, 3, stream, dcg, 'XLOG 4.1.4, XLOG 5') :-
         
   test5(X, ""), X == "bar".
         
runner_case(phrase, 3, stream, dcg, 'XLOG 4.1.4, XLOG 6') :-
         
   test6(1, X, ""), X == "foo".
         
runner_case(phrase, 3, stream, dcg, 'XLOG 4.1.4, XLOG 7') :-
         
   test7(2, X, ""), X == "bar".
         
runner_case(phrase, 3, stream, dcg, 'XLOG 4.1.4, XLOG 8') :-
         
   test8("foobaz", X), X == "baz".