package Sub::Nary;
-use 5.008001;
+use 5.008_001;
use strict;
use warnings;
-use Carp qw/croak/;
-use List::Util qw/reduce/;
+use Carp qw<croak>;
-use B qw/class ppname svref_2object OPf_KIDS/;
-
-use Test::More; use Data::Dumper;
+use B qw<class ppname svref_2object OPf_KIDS>;
=head1 NAME
=head1 VERSION
-Version 0.02
+Version 0.03
=cut
our $VERSION;
BEGIN {
- $VERSION = '0.02';
+ $VERSION = '0.03';
}
-our $DEBUG = 0;
-
=head1 SYNOPSIS
use Sub::Nary;
- my $sn = Sub::Nary->new();
+ my $sn = Sub::Nary->new;
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>
-The usual constructor. Currently takes no argument.
+ my $sn = Sub::Nary->new;
+
+The usual constructor.
+Currently takes no argument.
-=head2 C<nary $coderef>
+=head2 C<nary>
-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
+ my $res = $sn->nary($coderef);
+
+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 }
-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>
-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
=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 *
-As such,
+The total probability law for a given returning point is the convolution product of the probabilities of its list elements.
+
+As such,
sub notsosimple {
return 1, simple(), 2
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
return $r;
}
-sub add {
- reduce {
- $a->{$_} += $b->{$_} for keys %$b;
- $a
- } map { (ref) ? $_ : { $_ => 1 } } grep defined, @_;
-}
-
my %ops;
$ops{$_} = 1 for scalops;
-$ops{$_} = 0 for qw/stub nextstate pushmark iter unstack/;
-$ops{$_} = 1 for qw/padsv/;
-$ops{$_} = 'list' for qw/padav/;
-$ops{$_} = 'list' for qw/padhv rv2hv/;
-$ops{$_} = 'list' for qw/padany/;
-$ops{$_} = 'list' for qw/match entereval readline/;
+$ops{$_} = 0 for qw<stub nextstate pushmark iter unstack>;
+$ops{$_} = 1 for qw<padsv>;
+$ops{$_} = 'list' for qw<padav>;
+$ops{$_} = 'list' for qw<padhv rv2hv>;
+$ops{$_} = 'list' for qw<padany>;
+$ops{$_} = 'list' for qw<match entereval readline>;
$ops{each} = { 0 => 0.5, 2 => 0.5 };
$ops{stat} = { 0 => 0.5, 13 => 0.5 };
$ops{localtime} = do { my @a = localtime; scalar @a };
$ops{gmtime} = do { my @a = gmtime; scalar @a };
-$ops{$_} = { 0 => 0.5, 10 => 0.5 } for map "gpw$_", qw/nam uid ent/;
-$ops{$_} = { 0 => 0.5, 4 => 0.5 } for map "ggr$_", qw/nam gid ent/;
-$ops{$_} = 'list' for qw/ghbyname ghbyaddr ghostent/;
-$ops{$_} = { 0 => 0.5, 4 => 0.5 } for qw/gnbyname gnbyaddr gnetent/;
-$ops{$_} = { 0 => 0.5, 3 => 0.5 } for qw/gpbyname gpbynumber gprotoent/;
-$ops{$_} = { 0 => 0.5, 4 => 0.5 } for qw/gsbyname gsbyport gservent/;
+$ops{$_} = { 0 => 0.5, 10 => 0.5 } for map "gpw$_", qw<nam uid ent>;
+$ops{$_} = { 0 => 0.5, 4 => 0.5 } for map "ggr$_", qw<nam gid ent>;
+$ops{$_} = 'list' for qw<ghbyname ghbyaddr ghostent>;
+$ops{$_} = { 0 => 0.5, 4 => 0.5 } for qw<gnbyname gnbyaddr gnetent>;
+$ops{$_} = { 0 => 0.5, 3 => 0.5 } for qw<gpbyname gpbynumber gprotoent>;
+$ops{$_} = { 0 => 0.5, 4 => 0.5 } for qw<gsbyname gsbyport gservent>;
sub enter {
my ($self, $cv) = @_;
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) = @_;
my $n = name($op);
- diag "@ $n" if $DEBUG;
return add($self->inspect_kids($op)), undef if $n eq 'return';
my $meth = $self->can('pp_' . $n);
if (class($op) eq 'LOGOP' and not null $op->first) {
my @res;
- diag "? logop\n" if $DEBUG;
-
my $op = $op->first;
my ($r1, $l1) = $self->inspect($op);
- return $r1, $l1 if $r1 and zero $l1;
+ return $r1, $l1 if defined $r1 and zero $l1;
my $c = count $l1;
$op = $op->sibling;
if (null $op) {
# If the logop has no else branch, it can also return the *scalar* result of
# the conditional
- $l3 = { 1 => $c };
+ $l3 = { 1 => 1 };
} else {
($r3, $l3) = $self->inspect($op);
}
$op = $op->first;
redo;
}
- diag "> $n ($c)" if $DEBUG;
my ($rc, $lc) = $self->inspect($op);
+ $c = 1 - count $r;
$r = add $r, scale $c, $rc if defined $rc;
- if ($rc and not defined $lc) {
+ if (not defined $lc) {
@l = ();
last;
}
push @l, scale $c, $lc;
- $c *= count $lc if defined $lc;
}
- my $l = combine @l;
+ my $l = scale +(1 - count $r), normalize combine @l;
return $r, $l;
}
my ($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;
for (; not null $op->sibling; $op = $op->sibling) {
- my $n = name($op);
- next if $n eq 'nextstate';
- diag "* $n" if $DEBUG;
my ($rc, $lc) = $self->inspect($op);
- $r = add $r, scale $c, $rc if defined $rc;
- if (zero $lc) {
- $c = 1 - count $r;
- return $r, $c ? { 0 => $c } : undef
- }
+ return $rc, $lc if defined $rc and not defined $lc;
+ $r = add $r, scale $c, $rc;
$c *= count $lc;
}
$next = $next->sibling;
}
$n = name($op)
- } while ($op->flags & OPf_KIDS and { map { $_ => 1 } qw/null leave/ }->{$n});
- return 'list', undef unless { map { $_ => 1 } qw/gv refgen/ }->{$n};
+ } while ($op->flags & OPf_KIDS and { map { $_ => 1 } qw<null leave> }->{$n});
+ return 'list', undef unless { map { $_ => 1 } qw<gv refgen> }->{$n};
local $self->{sub} = 1;
my ($rc, $lc) = $self->inspect($op);
return $r, scale $c, $lc;
if ($c eq 'AV') {
$n = $sv->FILL + 1
} elsif ($c eq 'HV') {
- $n = 2 * $sv->FILL
+ $n = 2 * $sv->KEYS
}
return undef, $n
my ($self, $op) = @_;
$op = $op->first;
- my ($r, $l) = $self->inspect($op);
- if (name($op) ne 'const') {
- my $c = 1 - count $r;
- $l = $c ? { list => $c } : 0;
+ if (name($op) eq 'gv') {
+ return undef, { list => 1 };
}
- return $r, $l;
+
+ $self->inspect($op);
+}
+
+sub pp_sassign {
+ my ($self, $op) = @_;
+
+ my $r = ($self->inspect($op->first))[0];
+
+ my $c = 1 - count $r;
+ return $r, $c ? { 1 => $c } : undef
}
sub pp_aassign {
sub pp_leaveloop {
my ($self, $op) = @_;
- diag "* leaveloop" if $DEBUG;
-
$op = $op->first;
my ($r1, $l1);
- if (name($op) eq 'enteriter') {
+ my $for;
+ if (name($op) eq 'enteriter') { # for loop ?
+ $for = 1;
($r1, $l1) = $self->inspect($op);
- return $r1, $l1 if $r1 and zero $l1;
+ return $r1, $l1 if defined $r1 and zero $l1;
}
$op = $op->sibling;
- my $r = (name($op->first) eq 'and') ? ($self->inspect($op->first->first->sibling))[0]
- : ($self->inspect($op))[0];
+ my ($r2, $l2);
+ if (name($op->first) eq 'and') {
+ ($r2, $l2) = $self->inspect($op->first->first);
+ return $r2, $l2 if defined $r2 and zero $l2;
+ my $c = count $l2;
+ return { list => 1 }, undef if !$for and defined $r2;
+ my ($r3, $l3) = $self->inspect($op->first->first->sibling);
+ return { list => 1 }, undef if defined $r3 and defined $l3;
+ $r2 = add $r2, scale $c, $r3;
+ } else {
+ ($r2, $l2) = $self->inspect($op);
+ return { list => 1 }, undef if defined $r2 and defined $l2;
+ }
+
+ my $r = (defined $r1) ? add $r1, scale +(1 - count $r1), $r2
+ : $r2;
my $c = 1 - count $r;
- diag "& leaveloop" if $DEBUG;
return $r, $c ? { 0 => $c } : undef;
}
}
my $c = 1 - count $r;
- return $r, ($l && $c) ? { 'list' => $c } : undef
+ return $r, $c ? { 'list' => $c } : undef
}
sub pp_grepwhile {
$op = $op->first->sibling;
my ($r2, $l2) = $self->inspect($op->sibling);
- return $r2, $l2 if $r2 and zero $l2;
- diag Dumper [ $r2, $l2 ] if $DEBUG;
- my $c = count $l2; # First one to happen
+ return $r2, $l2 if defined $r2 and zero $l2;
+ my $c2 = count $l2; # First one to happen
my ($r1, $l1) = $self->inspect($op);
- diag Dumper [ $r1, $l1 ] if $DEBUG;
- return (add $r2, scale $c, $r1), undef if $r1 and zero $l1 and not zero $l2;
- return { 'list' => 1 }, undef if list $l2;
+ 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 $r = add $r2, scale $c,
- normalize
- add map { power $r1, $_, $l2->{$_} } keys %$l2;
- $c = 1 - count $r;
+ my $r = add $r2,
+ scale $c2,
+ add map { scale $l2->{$_}, cumulate $r1, $_, $c1 } keys %$l2;
+ my $c = 1 - count $r;
return $r, $c ? { ((zero $l2) ? 0 : 'list') => $c } : undef;
}
$op = $op->first->sibling;
my ($r2, $l2) = $self->inspect($op->sibling);
- return $r2, $l2 if $r2 and zero $l2;
- my $c = count $l2; # First one to happen
+ return $r2, $l2 if defined $r2 and zero $l2;
+ my $c2 = count $l2; # First one to happen
my ($r1, $l1) = $self->inspect($op);
- return (add $r2, scale $c, $r1), undef if $r1 and zero $l1 and not zero $l2;
- diag Dumper [ [ $r1, $l1 ], [ $r2, $l2 ] ] if $DEBUG;
+ 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 $r = add $r2, scale $c,
- normalize
- add map { power $r1, $_, $l2->{$_} } keys %$l2;
- $c = 1 - count $r;
+ my $r = add $r2,
+ scale $c2,
+ add map { scale $l2->{$_}, cumulate $r1, $_, $c1 } keys %$l2;
+ my $c = 1 - count $r;
my $l = scale $c, normalize add map { power $l1, $_, $l2->{$_} } keys %$l2;
return $r, $l;
}
L<perl> 5.8.1.
-L<Carp> (standard since perl 5), L<B> (since perl 5.005), L<XSLoader> (since perl 5.006) and L<List::Util> (since perl 5.007003).
+A C compiler.
+This module may happen to build with a C++ compiler as well, but don't rely on it, as no guarantee is made in this regard.
+
+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>.
-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
-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