


Devel::SelfStubbePerl)Programmers ReferenceDevel::SelfStubber(3p)


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/SelfStubber.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.



perl v5.10.1                2002-10-27                          1





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
       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.
































perl v5.10.1                2002-10-27                          2


