=head1 VERSION
-Version 0.02
+Version 0.03
=cut
our $VERSION;
BEGIN {
- $VERSION = '0.02';
+ $VERSION = '0.03';
}
=head1 SYNOPSIS
=head2 C<nary $coderef>
-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 :
- { 1 => 0.2, 2 => 0.4, 4 => 0.3, list => 0.1 }
+=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
+
+ { 1 => 0.2, 2 => 0.4, 4 => 0.25, list => 0.1, exit => 0.05 }
that is, we should get C<1> scalar C<1> time over C<5> and so on. The sum of all values is C<1>. The returned result, and all the results obtained from intermediate subs, are cached into the object.
=over 4
-=item * When branching, each branch is considered equally possible.
+=item *
+
+When branching, each branch is considered equally possible.
For example, the subroutine
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,
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> state is absorbing in regard of all the other ones.
+=item *
-This is just a pedantic way to say that "list + fixed length = list".
+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
sub listy {
is considered as always returning an unbounded list.
-Also, the convolution law does not behave the same when C<list> elements are involved : in the following example,
+Also, the convolution law does not behave the same when C<list> or C<exit> elements are involved : in the following example,
sub oneorlist {
if (rand < 0.1) {
my $r = add $self->inspect($op->first);
shift @{$self->{cv}};
- $r = { $r => 1 } unless ref $r;
$self->{cache}->{$tag} = { %$r };
return undef, $r;
}
my ($self, $op) = @_;
$op = $op->first while $op->flags & OPf_KIDS;
- return undef, 0 if null $op;
- if (name($op) eq 'pushmark') {
- $op = $op->sibling;
- return undef, 0 if null $op;
- }
+ # First must be a pushmark
+ $op = $op->sibling;
+ # Next must be non null - at worse it's the rv2cv
my $r;
my $c = 1;
return $self->{sub} ? $self->enter($self->const_sv($op)) : (undef, 1)
}
+sub pp_exit {
+ my ($self, $op) = @_;
+
+ my $r;
+ if ($op->flags & OPf_KIDS) {
+ ($r, my $l) = $self->inspect($op->first);
+ return $r, $l if defined $r and zero $l;
+ $r->{exit} = 1 - count $r;
+ } else {
+ $r = { 'exit' => 1 };
+ }
+
+ 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) = @_;
$self->inspect($op);
}
+sub pp_sassign {
+ my ($self, $op) = @_;
+
+ my $r = ($self->inspect($op->first))[0];
+
+ my $c = 1 - count $r;
+ return $r, $c ? { 1 => $c } : undef
+}
+
sub pp_aassign {
my ($self, $op) = @_;
$self->inspect($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) = @_;
=head1 BUGS
-Please report any bugs or feature requests to C<bug-b-nary at rt.cpan.org>, or through the web interface at L<http://rt.cpan.org/NoAuth/ReportBug.html?Queue=Sub-Nary>. I will be notified, and then you'll automatically be notified of progress on your bug as I make changes.
+Please report any bugs or feature requests to C<bug-sub-nary at rt.cpan.org>, or through the web interface at L<http://rt.cpan.org/NoAuth/ReportBug.html?Queue=Sub-Nary>. I will be notified, and then you'll automatically be notified of progress on your bug as I make changes.
=head1 SUPPORT
projects / perl / modules / Sub-Nary.git / blobdiff