indirect - Lexically warn about using the indirect object syntax.
VERSION
- Version 0.06
+ Version 0.19
SYNOPSIS
+ # In a script
no indirect;
my $x = new Apple 1, 2, 3; # warns
{
use indirect;
my $y = new Pear; # ok
+ {
+ no indirect hook => sub { die "You really wanted $_[0]\->$_[1] at $_[2]:$_[3]" };
+ my $z = new Pineapple 'fresh'; # croaks 'You really wanted Pineapple->new at blurp.pm:13'
+ }
}
+ try { ... }; # warns
+
no indirect ':fatal';
if (defied $foo) { ... } # croaks, note the typo
+ # From the command-line
+ perl -M-indirect -e 'my $x = new Banana;' # warns
+
+ # Or each time perl is ran
+ export PERL5OPT="-M-indirect"
+ perl -e 'my $y = new Coconut;' # warns
+
DESCRIPTION
When enabled (or disabled as some may prefer to say, since you actually
turn it on by calling "no indirect"), this pragma warns about indirect
object syntax constructs that may have slipped into your code. This
syntax is now considered harmful, since its parsing has many quirks and
- its use is error prone (when "sub" isn't defined, "sub $x" is actually
- interpreted as "$x->sub").
+ its use is error prone (when "swoosh" isn't defined, "swoosh $x"
+ actually compiles to "$x->swoosh").
- It currently does not warn when the object is enclosed between braces
- (like "meth { $obj } @args") or for core functions ("print" or "say").
- This may change in the future, or may be added as optional features that
- would be enabled by passing options to "unimport".
+ It currently does not warn for core functions ("print", "say", "exec" or
+ "system"). This may change in the future, or may be added as optional
+ features that would be enabled by passing options to "unimport".
This module is not a source filter.
METHODS
- "unimport @opts"
+ "unimport [ hook => $hook | ':fatal' ]"
Magically called when "no indirect @opts" is encountered. Turns the
- module on. If @opts contains ':fatal', the module will croak on the
- first indirect syntax met.
+ module on. The policy to apply depends on what is first found in @opts :
+
+ * If it's the string ':fatal', the compilation will croak on the first
+ indirect syntax met.
+
+ * If the key/value pair "hook => $hook" comes first, $hook will be
+ called for each error with a string representation of the object as
+ $_[0], the method name as $_[1], the current file as $_[2] and the
+ line number as $_[3]. If and only if the object is actually a block,
+ $_[0] is assured to start by '{'.
+
+ * Otherwise, a warning will be emitted for each indirect construct.
"import"
Magically called at each "use indirect". Turns the module off.
+FUNCTIONS
+ "msg $object, $method, $file, $line"
+ Returns the default error message generated by "indirect" when an
+ invalid construct is reported.
+
+CONSTANTS
+ "I_THREADSAFE"
+ True iff the module could have been built with thread-safety features
+ enabled.
+
+ "I_FORKSAFE"
+ True iff this module could have been built with fork-safety features
+ enabled. This will always be true except on Windows where it's false for
+ perl 5.10.0 and below .
+
+DIAGNOSTICS
+ "Indirect call of method "%s" on object "%s" at %s line %d."
+ The default warning/exception message thrown when an indirect call on an
+ object is found.
+
+ "Indirect call of method "%s" on a block at %s line %d."
+ The default warning/exception message thrown when an indirect call on a
+ block is found.
+
+ENVIRONMENT
+ "PERL_INDIRECT_PM_DISABLE"
+ If this environment variable is set to true when the pragma is used for
+ the first time, the XS code won't be loaded and, although the 'indirect'
+ lexical hint will be set to true in the scope of use, the pragma itself
+ won't do anything. In this case, the pragma will always be considered to
+ be thread-safe, and as such "I_THREADSAFE" will be true. This is useful
+ for disabling "indirect" in production environments.
+
+ Note that clearing this variable after "indirect" was loaded has no
+ effect. If you want to reenable the pragma later, you also need to
+ reload it by deleting the 'indirect.pm' entry from %INC.
+
+CAVEATS
+ The implementation was tweaked to work around several limitations of
+ vanilla "perl" pragmas : it's thread safe, and doesn't suffer from a
+ "perl 5.8.x-5.10.0" bug that causes all pragmas to propagate into
+ "require"d scopes.
+
+ "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 "meth $obj;" or "meth $obj 1").
+
+ With 5.8 perls, the pragma does not propagate into "eval STRING". This
+ is due to a shortcoming in the way perl handles the hints hash, which is
+ addressed in perl 5.10.
+
+ The search for indirect method calls happens before constant folding.
+ Hence "my $x = new Class if 0" will be caught.
+
DEPENDENCIES
- perl 5.9.4.
+ perl 5.8.
XSLoader (standard since perl 5.006).
ACKNOWLEDGEMENTS
Bram, for motivation and advices.
+ Andrew Main and Florian Ragwitz, for testing on real-life code and
+ reporting issues.
+
COPYRIGHT & LICENSE
- Copyright 2008 Vincent Pit, all rights reserved.
+ Copyright 2008-2009 Vincent Pit, all rights reserved.
This program is free software; you can redistribute it and/or modify it
under the same terms as Perl itself.
projects / perl / modules / indirect.git / blobdiff