10 indirect - Lexically warn about using the indirect object syntax.
27 my $x = new Apple 1, 2, 3; # warns
30 my $y = new Pear; # ok
32 no indirect hook => sub { die "You really wanted $_[0]\->$_[1]" };
33 my $z = new Pineapple 'fresh'; # croaks 'You really wanted Pineapple->new'
37 if (defied $foo) { ... } # croaks, note the typo
39 # From the command-line
40 perl -M-indirect -e 'my $x = new Banana;' # warns
42 # Or each time perl is ran
43 export PERL5OPT="-M-indirect"
44 perl -e 'my $y = new Coconut;' # warns
48 When enabled (or disabled as some may prefer to say, since you actually turn it on by calling C<no indirect>), this pragma warns about indirect object syntax constructs that may have slipped into your code.
49 This syntax is now considered harmful, since its parsing has many quirks and its use is error prone (when C<sub> isn't defined, C<sub $x> is actually interpreted as C<< $x->sub >>).
51 It currently does not warn when the object is enclosed between braces (like C<meth { $obj } @args>) or for core functions (C<print> or C<say>).
52 This may change in the future, or may be added as optional features that would be enabled by passing options to C<unimport>.
54 This module is B<not> a source filter.
60 XSLoader::load(__PACKAGE__, $VERSION);
65 =head2 C<< unimport [ hook => $hook | ':fatal' ] >>
67 Magically called when C<no indirect @opts> is encountered.
69 The policy to apply depends on what is first found in C<@opts> :
75 If it's the string C<':fatal'>, the compilation will croak on the first indirect syntax met.
79 If the key/value pair C<< hook => $hook >> comes first, C<$hook> will be called for each error with the object name as C<$_[0]> and the method name as C<$_[1]>.
83 Otherwise, a warning will be emitted for each indirect construct.
89 my $msg = sub { "Indirect call of method \"$_[1]\" on object \"$_[0]\"" };
99 } elsif ($arg eq ':fatal') {
100 $hook = sub { die $msg->(@_) };
104 $hook = sub { warn $msg->(@_) } unless defined $hook;
107 $^H{+(__PACKAGE__)} = _tag($hook);
114 Magically called at each C<use indirect>. Turns the module off.
119 $^H{+(__PACKAGE__)} = undef;
125 =head2 C<I_THREADSAFE>
127 True iff the module could have been built when thread-safety features.
131 C<meth $obj> (no semicolon) at the end of a file won't be seen as an indirect object syntax, although it will as soon as there is another token before the end (as in C<meth $obj;> or C<meth $obj 1>).
133 With 5.8 perls, the pragma does not propagate into C<eval STRING>.
134 This is due to a shortcoming in the way perl handles the hints hash, which is addressed in perl 5.10.
140 L<XSLoader> (standard since perl 5.006).
144 Vincent Pit, C<< <perl at profvince.com> >>, L<http://www.profvince.com>.
146 You can contact me by mail or on C<irc.perl.org> (vincent).
150 Please report any bugs or feature requests to C<bug-indirect at rt.cpan.org>, or through the web interface at L<http://rt.cpan.org/NoAuth/ReportBug.html?Queue=indirect>.
151 I will be notified, and then you'll automatically be notified of progress on your bug as I make changes.
155 You can find documentation for this module with the perldoc command.
159 Tests code coverage report is available at L<http://www.profvince.com/perl/cover/indirect>.
161 =head1 ACKNOWLEDGEMENTS
163 Bram, for motivation and advices.
165 =head1 COPYRIGHT & LICENSE
167 Copyright 2008-2009 Vincent Pit, all rights reserved.
169 This program is free software; you can redistribute it and/or modify it under the same terms as Perl itself.