Predicate not calling in SWI-Prolog

0
votes
solve([("ab","abab"), ("b","a"), ("aba","b"), ("aa","a")], Solution)

Answer has been delivered.

1
prologswi-prolog

1 Answers

3
votes

SWI-Prolog 7.x changed the default value of the double_quotes flag from codes to string. This is apparently what's causing the problem you describe. If you add, at the top of the source file with the code you posted, the following directive:

:- set_prolog_flag(double_quotes, codes).

You should get:

?- solve([("ab","abab"), ("b","a"), ("aba","b"), ("aa","a")], Solution).
Solution = [4, 4, 2, 1] ;
Solution = [1, 1, 3, 2, 2, 4, 4] ;
Solution = [4, 4, 2, 1, 4, 4, 2, 1] ;
Solution = [1, 1, 3, 2, 2, 4, 3, 4, 2|...] ;
Solution = [1, 1, 3, 2, 2, 4, 4, 4, 4|...] ;