MirOS Manual: Devel::SelfStubber(3p)


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 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.

perl v5.8.8                2005-02-05                           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 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.

perl v5.8.8                2005-02-05                           2

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