diff options
Diffstat (limited to 'contrib/perl5/lib/base.pm')
| -rw-r--r-- | contrib/perl5/lib/base.pm | 25 |
1 files changed, 20 insertions, 5 deletions
diff --git a/contrib/perl5/lib/base.pm b/contrib/perl5/lib/base.pm index 3500cbfb8985..3cb42f5bfa2f 100644 --- a/contrib/perl5/lib/base.pm +++ b/contrib/perl5/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 @@ -35,22 +44,30 @@ L<fields> package base; +use 5.005_64; +our $VERSION = "1.01"; + sub import { my $class = shift; my $fields_base; + my $pkg = caller(0); foreach my $base (@_) { - unless (defined %{"$base\::"}) { + next if $pkg->isa($base); + push @{"$pkg\::ISA"}, $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. die if $@ && $@ !~ /^Can't locate .*? at \(eval /; - unless (defined %{"$base\::"}) { + unless (%{"$base\::"}) { require Carp; Carp::croak("Base class package \"$base\" is empty.\n", "\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 @@ -66,8 +83,6 @@ sub import { } } } - my $pkg = caller(0); - push @{"$pkg\::ISA"}, @_; if ($fields_base) { require fields; fields::inherit($pkg, $fields_base); |