Question

I want to print matrix, each row in a separate line, for example

?- print_matrix([[a,b,c],[d,e,f]]).

And i want to get

[a,b,c]
[d,e,f]

Answer 1

The simplest way to do it is to use write and nl in a recursive rule, like this:

print_matrix([]).
print_matrix([H|T]) :- write(H), nl, print_matrix(T).

This is the “classic” Prolog solution for list processing, with a fact handling the empty list, and a rule that processes header elements one-by-one.