[m-users.] Display all predicate values

[Philippe de Rochambeau]

Hello,
what is the idiomatic way in Mercury to display all values that match the friend  predicate?


:- pred friend(string).
:- mode friend(out).
friend("Mark").
friend("Jack").
friend("Andrew »).

main(!IO) :-
  friend(Who),
  lookup(Who, 1, Val),
  io.write(Who, !IO).


I’ve tried using lookup, but it’s Who is not an array.

Many thanks.

Best regards,

Philippe


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