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author | Andreas König <a.koenig@mind.de> | 1999-03-19 07:00:28 +0100 |
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committer | Gurusamy Sarathy <gsar@cpan.org> | 1999-05-05 06:55:21 +0000 |
commit | b8bc843f4b88497de8b7d2b8ca0b37a92d610dc4 (patch) | |
tree | a85da298f98dc1ecf58f0b030e150fb39ef58268 /lib/base.pm | |
parent | 0fd7581c22cd07e1d37e8a54fe87bd9bf54c7cf9 (diff) | |
download | perl-b8bc843f4b88497de8b7d2b8ca0b37a92d610dc4.tar.gz |
load base packages based on nonexistent $VERSION
Message-ID: <sfcsob2m5ub.fsf@dubravka.in-berlin.de>
Subject: Re: base.pm flaw
p4raw-id: //depot/perl@3302
Diffstat (limited to 'lib/base.pm')
-rw-r--r-- | lib/base.pm | 17 |
1 files changed, 15 insertions, 2 deletions
diff --git a/lib/base.pm b/lib/base.pm index 3500cbfb89..9a733eada8 100644 --- a/lib/base.pm +++ b/lib/base.pm @@ -19,12 +19,21 @@ Roughly similar in effect to Will also initialize the %FIELDS hash if one of the base classes has it. Multiple inheritance of %FIELDS is not supported. The 'base' -pragma will croak if multiple base classes has a %FIELDS hash. See +pragma will croak if multiple base classes have a %FIELDS hash. See L<fields> for a description of this feature. When strict 'vars' is in scope I<base> also let you assign to @ISA without having to declare @ISA with the 'vars' pragma first. +If any of the base classes are not loaded yet, I<base> silently +C<require>s them. Whether to C<require> a base class package is +determined by the absence of a global $VERSION in the base package. +If $VERSION is not detected even after loading it, <base> will +define $VERSION in the base package, setting it to the string +C<-1, defined by base.pm>. + +=head1 HISTORY + This module was introduced with Perl 5.004_04. =head1 SEE ALSO @@ -34,13 +43,15 @@ L<fields> =cut package base; +use vars qw($VERSION); +$VERSION = "1.00"; sub import { my $class = shift; my $fields_base; foreach my $base (@_) { - unless (defined %{"$base\::"}) { + unless (exists ${"$base\::"}{VERSION}) { eval "require $base"; # Only ignore "Can't locate" errors from our eval require. # Other fatal errors (syntax etc) must be reported. @@ -51,6 +62,8 @@ sub import { "\t(Perhaps you need to 'use' the module ", "which defines that package first.)"); } + ${"$base\::VERSION"} = "-1, set by base.pm" + unless exists ${"$base\::"}{VERSION}; } # A simple test like (defined %{"$base\::FIELDS"}) will |