-Takes a code reference to a named or anonymous subroutine, and returns a hash reference whose keys are the possible numbers of returning scalars, and the corresponding values the "probability" to get them. The special key C<'list'> is used to denote a possibly infinite number of returned arguments. The return value hence would look at
+Takes a code reference to a named or anonymous subroutine, and returns a hash reference whose keys are the possible numbers of returning scalars, and the corresponding values the "probability" to get them. A few special keys are also used :
+
+=over 4
+
+=item *
+
+C<'list'> is used to denote a possibly infinite number of returned arguments ;
+
+=item *
+
+C<'exit'> gives the probability for C<exit> to be called somewhere in the code.
+
+=back
+
+The return value hence would look at