Sub::Nary - Try to count how many elements a subroutine can return in list context.
=head1 VERSION
=head1 NAME
Sub::Nary - Try to count how many elements a subroutine can return in list context.
=head1 VERSION
-Version 0.02
+Version 0.03
=cut
our $VERSION;
BEGIN {
=cut
our $VERSION;
BEGIN {
- $VERSION = '0.02';
+ $VERSION = '0.03';
}
}
-our $DEBUG = 0;
-
=head1 SYNOPSIS
use Sub::Nary;
=head1 SYNOPSIS
use Sub::Nary;
- my $sn = Sub::Nary->new();
+ my $sn = Sub::Nary->new;
my $r = $sn->nary(\&hlagh);
=head1 DESCRIPTION
my $r = $sn->nary(\&hlagh);
=head1 DESCRIPTION
-This module uses the L<B> framework to walk into subroutines and try to guess how many scalars are likely to be returned in list context. It's not always possible to give a definitive answer to this question at compile time, so the results are given in terms of "probability of return" (to be understood in a sense described below).
+This module uses the L<B> framework to walk into subroutines and try to guess how many scalars are likely to be returned in list context.
+It's not always possible to give a definitive answer to this question at compile time, so the results are given in terms of "probability of return" (to be understood in a sense described below).
=head1 METHODS
=head2 C<new>
=head1 METHODS
=head2 C<new>
-The usual constructor. Currently takes no argument.
+ my $sn = Sub::Nary->new;
+
+The usual constructor.
+Currently takes no argument.
+
+=head2 C<nary>
-=head2 C<nary $coderef>
+ my $res = $sn->nary($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 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
{ 1 => 0.2, 2 => 0.4, 4 => 0.3, list => 0.1 }
{ 1 => 0.2, 2 => 0.4, 4 => 0.3, list => 0.1 }
-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.
+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.
=head2 C<flush>
=head2 C<flush>
-Flushes the L<Sub::Nary> object cache. Returns the object itself.
+Flushes the L<Sub::Nary> object cache.
+Returns the object itself.
=head1 PROBABILITY OF RETURN
=head1 PROBABILITY OF RETURN
@@ -63,7+70,9 @@ The probability is computed as such :
=over 4
=over 4
-=item * When branching, each branch is considered equally possible.
+=item *
+
+When branching, each branch is considered equally possible.
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>.
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,
+As such,
sub notsosimple {
return 1, simple(), 2
sub notsosimple {
return 1, simple(), 2
@@ -105,11+116,16 @@ 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.
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 } >>.
+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 *
+
+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".
That's why
This is just a pedantic way to say that "list + fixed length = list".
+ return (add $r2, scale $c2, $r1), undef if defined $r1 and zero $l1
+ and not zero $l2;
my $c1 = count $l1;
$l2 = { $l2 => 1 } unless ref $l2;
my $c1 = count $l1;
$l2 = { $l2 => 1 } unless ref $l2;
@@ -606,17+612,18 @@ C<wantarray> isn't specialized when encountered in the optree.
L<perl> 5.8.1.
L<perl> 5.8.1.
-L<Carp> (standard since perl 5), L<B> (since perl 5.005) and L<XSLoader> (since perl 5.006).
+L<Carp> (standard since perl 5), L<B> (since perl 5.005) and L<XSLoader> (since perl 5.6.0).
=head1 AUTHOR
Vincent Pit, C<< <perl at profvince.com> >>, L<http://www.profvince.com>.
=head1 AUTHOR
Vincent Pit, C<< <perl at profvince.com> >>, L<http://www.profvince.com>.
-You can contact me by mail or on #perl @ FreeNode (vincent or Prof_Vince).
+You can contact me by mail or on C<irc.perl.org> (vincent).
=head1 BUGS
=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.