I've been setting up a standard module.pm template for
several folks to use.
The perlmod man page suggests this:
use Exporter ();
our ($VERSION, @ISA, @EXPORT, @EXPORT_OK, %EXPORT_TAGS);
# set the version for version checking
$VERSION = 1.00;
# if using RCS/CVS, this may be preferred
$VERSION = sprintf "%d.%03d", q$Revision: 1.1 $ =~ /(\d+)/g;
@ISA = qw(Exporter);
@EXPORT = qw(&func1 &func2 &func4);
%EXPORT_TAGS = ( ); # eg: TAG => [ qw!name1 name2! ],
# your exported package globals go here,
# as well as any optionally exported functions
@EXPORT_OK = qw($Var1 %Hashit &func3);
But that ExtUtils-ModuleMaker-0.32 (which I found via a
module best-practices thread) does this:
use Exporter ();
use vars qw ($VERSION @ISA @EXPORT @EXPORT_OK %EXPORT_TAGS);
$VERSION = 0.01;
@ISA = qw (Exporter);
#Give a hoot don't pollute, do not export more than needed by
@EXPORT = qw ();
@EXPORT_OK = qw ();
%EXPORT_TAGS = ();
and other examples (that I can't find at the moment) do
without the BEGIN block.
I'd like to be able to explain the differences to other
folks, but don't know all of the history, so I have a
- I think that "use vars" is obsolete and that "our"
is prefered. But I think that using "our" impacts
backward compatibility? Or is there more going on?
- I think that modules should put their module setup
stuff (VERSION, ISA, EXPORT*) in a BEGIN block so that
it's available at compile time (since that what the
BEGIN block does...), but I'm not clear on who takes
advantage of it.
- In order to leverage the justification in 2., should
I put all of the module's that the package in question
"uses" into the begin block, or just the module def'n
Edit by tye, replace PRE with CODE