Explain how we treat core functions in regard to probabilities of return

diff --git a/lib/Sub/Nary.pm b/lib/Sub/Nary.pm
index a6b97e0f401d0ab56a0b47281c7cc817ce22eff7..219e8c3dc7aca24f522eaeaae80f7832f513c025 100644 (file)
--- a/lib/Sub/Nary.pm
+++ b/lib/Sub/Nary.pm
@@ -102,6 +102,10 @@ returns C<3> or C<4> arguments with probability C<1/2> ; and
 
 never returns C<1> argument but returns C<2> with probability C<1/2 * 1/2 = 1/4>, C<3> with probability C<1/2 * 1/2 + 1/2 * 1/2 = 1/2> and C<4> with probability C<1/4> too.
 
+=item * If a core function may return different numbers of scalars, each kind is considered equally possible.
+
+For example, C<stat> returns C<13> elements on success and C<0> on error. The according probability will then be C<< { 0 => 0.5, 13 => 0.5 } >>.
+
 =item * The C<list> state is absorbing in regard of all the other ones.
 
 This is just a pedantic way to say that "list + fixed length = list".