Devel::SelfStubbePerl Programmers Reference Devel::SelfStubber(3)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
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.
16/Sep/1999 perl 5.005, patch 03 1
Devel::SelfStubbePerl Programmers Reference Devel::SelfStubber(3)
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
'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 SelfStubber actually uses the SelfLoader
to determine which stubs are needed.
16/Sep/1999 perl 5.005, patch 03 2