use string notation as discussed on #scryer IRC

diff --git a/src/lib/lists.pl b/src/lib/lists.pl
index 5eef37c2487126b72a531188391607cecd5ddd26..a037fd85d8011ee6ce1f23f0dc69723cccb03ce9 100644 (file)
--- a/src/lib/lists.pl
+++ b/src/lib/lists.pl
@@ -67,14 +67,12 @@ resource_error(Resource, Context) :-
 % to create a list full of free variables with N length.
 %
 % ```
-% ?- length([a,b,c], 3).
+% ?- length("abc", 3).
 %    true.
-% ?- length([a,b,c], N).
+% ?- length("abc", N).
 %    N = 3.
 % ?- length(Xs, 3).
 %    Xs = [_A, _B, _C].
-% ?- length("chars", N).
-%    N = 5.
 % ```
 
 length(Xs0, N) :-