Add support for die()

[perl/modules/Sub-Nary.git] / lib / Sub / Nary.pm

diff --git a/lib/Sub/Nary.pm b/lib/Sub/Nary.pm
index 73345b506a4ccfc870ab848ce6b527bf8cf74028..159dd8e6bc9a31fb753478eec7c573feb852bad1 100644 (file)
--- a/lib/Sub/Nary.pm
+++ b/lib/Sub/Nary.pm
@@ -73,7 +73,9 @@ The probability is computed as such :
 
 =over 4
 
-=item * When branching, each branch is considered equally possible.
+=item *
+
+When branching, each branch is considered equally possible.
 
 For example, the subroutine
 
@@ -99,7 +101,9 @@ As for
 
 it is considered to return C<3> scalars with probability C<1/2>, C<2> with probability C<1/2 * 1/2 = 1/4> and C<1> (when the two tests fail, the last computed value is returned, which here is C<< $x > 0.9 >> evaluated in the scalar context of the test) with remaining probability C<1/4>.
 
-=item * The total probability law for a given returning point is the convolution product of the probabilities of its list elements.
+=item *
+
+The total probability law for a given returning point is the convolution product of the probabilities of its list elements.
 
 As such, 
 
@@ -115,11 +119,15 @@ 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.
+=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> and C<exit> states are absorbing in regard of all the other ones.
+=item *
+
+The C<list> and C<exit> states are absorbing in regard of all the other ones.
 
 This is just a pedantic way to say that C<list + fixed length = list>, C<exit + fixed length = exit>, but note also that C<exit + list = exit>.
 That's why
@@ -418,6 +426,20 @@ sub pp_exit {
  return $r, undef;
 }
 
+sub pp_die {
+ my ($self, $op) = @_;
+
+ my ($r, undef) = $self->inspect_kids($op);
+ if (defined $r) {
+  my $c = 1 - count $r;
+  $r->{die} = $c if $c;
+ } else {
+  $r = { die => 1 };
+ }
+
+ return $r, undef;
+}
+
 sub pp_goto {
  my ($self, $op) = @_;
 
@@ -495,6 +517,18 @@ sub pp_aassign {
  $self->inspect($op);
 }
 
+sub pp_leavetry {
+ my ($self, $op) = @_;
+
+ my ($r, $l) = $self->inspect_kids($op);
+ if (defined $r) {
+  my $d = delete $r->{die};
+  $r->{0} += $d if defined $d;
+ }
+
+ return $r, $l;
+}
+
 sub pp_leaveloop {
  my ($self, $op) = @_;