NAME
- indirect - Lexically warn about using the indirect object syntax.
+ indirect - Lexically warn about using the indirect method call syntax.
VERSION
- Version 0.25
+ Version 0.26
SYNOPSIS
- # In a script
- no indirect;
+ In a script :
+
+ no indirect; # lexically enables the pragma
my $x = new Apple 1, 2, 3; # warns
{
- use indirect;
- my $y = new Pear; # ok
+ use indirect; # lexically disables the pragma
+ my $y = new Pear; # legit, does not warn
{
- 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'
+ # lexically specify an hook called for each indirect construct
+ no indirect hook => sub {
+ die "You really wanted $_[0]\->$_[1] at $_[2]:$_[3]"
+ };
+ my $z = new Pineapple 'fresh'; # croaks 'You really wanted...'
}
}
- try { ... }; # warns
+ try { ... }; # warns if try() hasn't been declared in this package
- no indirect ':fatal'; # or 'FATAL', or ':Fatal' ...
+ no indirect 'fatal'; # or ':fatal', 'FATAL', ':Fatal' ...
if (defied $foo) { ... } # croaks, note the typo
- # From the command-line
- perl -M-indirect -e 'my $x = new Banana;' # warns
+ Global uses :
+
+ # Globally enable the pragma from the command-line
+ perl -M-indirect=global -e 'my $x = new Banana;' # warns
- # Or each time perl is ran
- export PERL5OPT="-M-indirect"
- perl -e 'my $y = new Coconut;' # warns
+ # Globally enforce the pragma each time perl is executed
+ export PERL5OPT="-M-indirect=global,fatal"
+ perl -e 'my $y = new Coconut;' # croaks
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.
+ When enabled, this pragma warns about indirect method calls that are
+ present in your code.
- This syntax is now considered harmful, since its parsing has many quirks
- and its use is error prone (when "swoosh" is not defined, "swoosh $x"
- actually compiles to "$x->swoosh"). In
+ The indirect syntax is now considered harmful, since its parsing has
+ many quirks and its use is error prone : when the subroutine "foo" has
+ not been declared in the current package, "foo $x" actually compiles to
+ "$x->foo", and "foo { key => 1 }" to "'key'->foo(1)". In
<http://www.shadowcat.co.uk/blog/matt-s-trout/indirect-but-still-fatal>,
- Matt S. Trout gives an example of an indirect construct that can cause a
- particularly bewildering error.
+ Matt S. Trout gives an example of an undesirable indirect method call on
+ a block that can cause a particularly bewildering error.
- 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 pragma 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 [ hook => $hook | ':fatal', 'FATAL', ... ]"
+ "unimport [ 'global', hook => $hook | 'fatal' ]"
Magically called when "no indirect @opts" is encountered. Turns the
module on. The policy to apply depends on what is first found in @opts :
* If it is a string that matches "/^:?fatal$/i", the compilation will
- croak on the first indirect syntax met.
+ croak when the first indirect method call is found.
+
+ This option is mutually exclusive with the 'hook' option.
* If the key/value pair "hook => $hook" comes first, $hook will be
called for each error with a string representation of the object as
line number as $_[3]. If and only if the object is actually a block,
$_[0] is assured to start by '{'.
- * Otherwise, a warning will be emitted for each indirect construct.
+ This option is mutually exclusive with the 'fatal' option.
+
+ * If none of "fatal" and "hook" are specified, a warning will be
+ emitted for each indirect method call.
+
+ * If @opts contains a string that matches "/^:?global$/i", the pragma
+ will be globally enabled for all code compiled after the current "no
+ indirect" statement, except for code that is in the lexical scope of
+ "use indirect". This option may come indifferently before or after
+ the "fatal" or "hook" options, in the case they are also passed to
+ "unimport".
+
+ The global policy applied is the one resulting of the "fatal" or
+ "hook" options, thus defaults to a warning when none of those are
+ specified :
+
+ no indirect 'global'; # warn for any indirect call
+ no indirect qw<global fatal>; # die on any indirect call
+ no indirect 'global', hook => \&hook # custom global action
+
+ Note that if another policy is installed by a "no indirect"
+ statement further in the code, it will overrule the global policy :
+
+ no indirect 'global'; # warn globally
+ {
+ no indirect 'fatal'; # throw exceptions for this lexical scope
+ ...
+ require Some::Module; # the global policy will apply for the
+ # compilation phase of this module
+ }
"import"
Magically called at each "use indirect". Turns the module off.
+ As explained in "unimport"'s description, an "use indirect" statement
+ will lexically override a global policy previously installed by "no
+ indirect 'global', ..." (if there's one).
+
FUNCTIONS
"msg $object, $method, $file, $line"
- Returns the default error message generated by "indirect" when an
- invalid construct is reported.
+ Returns the default error message that "indirect" generates when an
+ indirect method call is reported.
CONSTANTS
"I_THREADSAFE"
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.
+ The default warning/exception message thrown when an indirect method
+ 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.
+ The default warning/exception message thrown when an indirect method
+ call on a block is found.
ENVIRONMENT
"PERL_INDIRECT_PM_DISABLE"
"require"d scopes.
Before "perl" 5.12, "meth $obj" (no semicolon) at the end of a file is
- not seen as an indirect object syntax, although it is as soon as there
- is another token before the end (as in "meth $obj;" or "meth $obj 1").
- If you use "perl" 5.12 or greater, those constructs are correctly
- reported.
+ not seen as an indirect method call, although it is as soon as there is
+ another token before the end (as in "meth $obj;" or "meth $obj 1"). If
+ you use "perl" 5.12 or greater, those constructs are correctly reported.
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
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.
- XSLoader (standard since perl 5.006).
+ Carp (standard since perl 5), XSLoader (since perl 5.006).
AUTHOR
Vincent Pit, "<perl at profvince.com>", <http://www.profvince.com>.
projects / perl / modules / indirect.git / commitdiff