Devel::SelfStubbePerl Programmers Reference Devel::SelfStubber(3)NAMEDevel::SelfStubber - generate stubs for a SelfLoading mod
ule
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 cor
rectly
use Devel::SelfStubber;
$Devel::SelfStubber::JUST_STUBS=0;
Devel::SelfStubber->stub('MODULENAME','MY_LIB_DIR');
MODULENAME is the Perl module name, e.g. Devel::SelfStub
ber, 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.
So, for classes and subclasses to have inheritance cor
rectly work with autoloading, you need to ensure stubs are
loaded.
The SelfLoader can load stubs automatically at module ini
tialization with the statement 'Self
Loader->load_stubs()';, but you may wish to avoid having
the stub loading overhead associated with your
initialization (though note that the Self
Loader::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 auto
matic 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 cor
rectly.
At the very least, this is useful to see what the Self
Loader thinks are stubs - in order to ensure future ver
sions of the SelfStubber remain in step with the Self
Loader, the SelfStubber actually uses the SelfLoader to
determine which stubs are needed.
2001-03-03 perl v5.6.1 Devel::SelfStubber(3)
