Devel::SelfStubber(3pm) Perl Programmers Reference Guide Devel::SelfStubber(3pm)
NAME
Devel::SelfStubber - generate stubs for a SelfLoading module
SYNOPSIS
To generate just the stubs:
use Devel::SelfStubber;
Devel::SelfStubber->stub('MODULENAME','MY_LIB_DIR');
or to generate the whole module with stubs inserted correctly
use Devel::SelfStubber;
$Devel::SelfStubber::JUST_STUBS=0;
Devel::SelfStubber->stub('MODULENAME','MY_LIB_DIR');
MODULENAME is the Perl module name, e.g. Devel::SelfStubber, NOT 'Devel/SelfStubber' or 'Devel/SelfS-tubber.pm'. 'Devel/SelfStubber.pm'.
tubber.pm'.
MY_LIB_DIR defaults to '.' if not present.
DESCRIPTION
Devel::SelfStubber prints the stubs you need to put in the module before the __DATA__ token (or you
can get it to print the entire module with stubs correctly placed). The stubs ensure that if a method
is called, it will get loaded. They are needed specifically for inherited autoloaded methods.
This is best explained using the following example:
Assume four classes, A,B,C & D.
A is the root class, B is a subclass of A, C is a subclass of B, and D is another subclass of A.
A
/ \
B D
/
C
If D calls an autoloaded method 'foo' which is defined in class A, then the method is loaded into
class A, then executed. If C then calls method 'foo', and that method was reimplemented in class B,
but set to be autoloaded, then the lookup mechanism never gets to the AUTOLOAD mechanism in B because
it first finds the method already loaded in A, and so erroneously uses that. If the method foo had
been stubbed in B, then the lookup mechanism would have found the stub, and correctly loaded and used
the sub from B.
So, for classes and subclasses to have inheritance correctly work with autoloading, you need to
ensure stubs are loaded.
The SelfLoader can load stubs automatically at module initialization with the statement 'Self-Loader->load_stubs()';, 'SelfLoader->load_stubs()';,
Loader->load_stubs()';, but you may wish to avoid having the stub loading overhead associated with
your initialization (though note that the SelfLoader::load_stubs method will be called sooner or
later - at latest when the first sub is being autoloaded). In this case, you can put the sub stubs
before the __DATA__ token. This can be done manually, but this module allows automatic generation of
the stubs.
By default it just prints the stubs, but you can set the global $Devel::SelfStubber::JUST_STUBS to 0
and it will print out the entire module with the stubs positioned correctly.
At the very least, this is useful to see what the SelfLoader thinks are stubs - in order to ensure
future versions of the SelfStubber remain in step with the SelfLoader, the SelfStubber actually uses
the SelfLoader to determine which stubs are needed.
perl v5.8.8 2001-09-21 Devel::SelfStubber(3pm)
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