Devel::SelfStubbePerl)Programmers ReferenceDevel::SelfStubber(3p)NAMEDevel::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/SelfStubber.pm'.
MY_LIB_DIR defaults to '.' if not present.
DESCRIPTIONDevel::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 exe-
cuted. 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.
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Devel::SelfStubbePerl)Programmers ReferenceDevel::SelfStubber(3p)
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 ini-
tialization with the statement 'SelfLoader->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 SelfS-
tubber actually uses the SelfLoader to determine which stubs
are needed.
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