2 indirect - Lexically warn about using the indirect object syntax.
10 my $x = new Apple 1, 2, 3; # warns
13 my $y = new Pear; # ok
15 no indirect hook => sub { die "You really wanted $_[0]\->$_[1] at $_[2]:$_[3]" };
16 my $z = new Pineapple 'fresh'; # croaks 'You really wanted Pineapple->new at blurp.pm:13'
22 if (defied $foo) { ... } # croaks, note the typo
24 # From the command-line
25 perl -M-indirect -e 'my $x = new Banana;' # warns
27 # Or each time perl is ran
28 export PERL5OPT="-M-indirect"
29 perl -e 'my $y = new Coconut;' # warns
32 When enabled (or disabled as some may prefer to say, since you actually
33 turn it on by calling "no indirect"), this pragma warns about indirect
34 object syntax constructs that may have slipped into your code. This
35 syntax is now considered harmful, since its parsing has many quirks and
36 its use is error prone (when "swoosh" isn't defined, "swoosh $x"
37 actually compiles to "$x->swoosh").
39 It currently does not warn for core functions ("print", "say", "exec" or
40 "system"). This may change in the future, or may be added as optional
41 features that would be enabled by passing options to "unimport".
43 This module is not a source filter.
46 "unimport [ hook => $hook | ':fatal' ]"
47 Magically called when "no indirect @opts" is encountered. Turns the
48 module on. The policy to apply depends on what is first found in @opts :
50 * If it's the string ':fatal', the compilation will croak on the first
53 * If the key/value pair "hook => $hook" comes first, $hook will be
54 called for each error with a string representation of the object as
55 $_[0], the method name as $_[1], the current file as $_[2] and the
56 line number as $_[3]. If and only if the object is actually a block,
57 $_[0] is assured to start by '{'.
59 * Otherwise, a warning will be emitted for each indirect construct.
62 Magically called at each "use indirect". Turns the module off.
65 "msg $object, $method, $file, $line"
66 Returns the default error message generated by "indirect" when an
67 invalid construct is reported.
71 True iff the module could have been built with thread-safety features
75 "Indirect call of method "%s" on object "%s" at %s line %d."
76 The default warning/exception message thrown when an indirect call on an
79 "Indirect call of method "%s" on a block at %s line %d."
80 The default warning/exception message thrown when an indirect call on a
84 "PERL_INDIRECT_PM_DISABLE"
85 If this environment variable is set to true when the pragma is used for
86 the first time, the XS code won't be loaded and, although the 'indirect'
87 lexical hint will be set to true in the scope of use, the pragma itself
88 won't do anything. This is useful for disabling "indirect" in production
91 Note that clearing this variable after "indirect" was loaded has no
92 effect. If you want to reenable the pragma later, you also need to
93 reload it by deleting the 'indirect.pm' entry from %INC.
96 The implementation was tweaked to work around several limitations of
97 vanilla "perl" pragmas : it's thread safe, and doesn't suffer from a
98 "perl 5.8.x-5.10.0" bug that causes all pragmas to propagate into
101 "meth $obj" (no semicolon) at the end of a file won't be seen as an
102 indirect object syntax, although it will as soon as there is another
103 token before the end (as in "meth $obj;" or "meth $obj 1").
105 With 5.8 perls, the pragma does not propagate into "eval STRING". This
106 is due to a shortcoming in the way perl handles the hints hash, which is
107 addressed in perl 5.10.
109 The search for indirect method calls happens before constant folding.
110 Hence "my $x = new Class if 0" will be caught.
115 XSLoader (standard since perl 5.006).
118 Vincent Pit, "<perl at profvince.com>", <http://www.profvince.com>.
120 You can contact me by mail or on "irc.perl.org" (vincent).
123 Please report any bugs or feature requests to "bug-indirect at
124 rt.cpan.org", or through the web interface at
125 <http://rt.cpan.org/NoAuth/ReportBug.html?Queue=indirect>. I will be
126 notified, and then you'll automatically be notified of progress on your
127 bug as I make changes.
130 You can find documentation for this module with the perldoc command.
134 Tests code coverage report is available at
135 <http://www.profvince.com/perl/cover/indirect>.
138 Bram, for motivation and advices.
140 Andrew Main and Florian Ragwitz, for testing on real-life code and
144 Copyright 2008-2009 Vincent Pit, all rights reserved.
146 This program is free software; you can redistribute it and/or modify it
147 under the same terms as Perl itself.