:- module martians. :- interface. :- import_module io. :- pred main(io::di, io::uo) is cc_multi. :- implementation. :- type martian ---> ngtrks; pgvdrk. :- pred small(martian::out) is det. :- pred green(martian::out) is multi. :- pred martian(martian::out) is multi. :- pred jumping(martian::out) is det. :- pred intelligent(martian::out) is nondet. small(ngtrks). green(ngtrks). martian(pgvdrk). jumping(pgvdrk). green(X) :- jumping(X). martian(X) :- small(X), jumping(X). intelligent(X) :- green(X), martian(X). main(!IO) :- io.write_string("Que marciano es inteligente?: ", !IO), ( if intelligent(X) then io.write(X, !IO), io.write_string(" es inteligente\n", !IO) else io.write_string(" no se puede determinar\n", !IO) ).