New tlperl part VIII

git-svn-id: svn://tug.org/texlive/trunk@21430 c570f23f-e606-0410-a88d-b1316a301751

1 files changed, 136 insertions, 0 deletions

diff --git a/Master/tlpkg/tlperl/lib/parent.pm b/Master/tlpkg/tlperl/lib/parent.pm
new file mode 100644
index 00000000000..a18526bb519
--- /dev/null
+++ b/Master/tlpkg/tlperl/lib/parent.pm
@@ -0,0 +1,136 @@
+package parent;
+use strict;
+use vars qw($VERSION);
+$VERSION = '0.223';
+
+sub import {
+    my $class = shift;
+
+    my $inheritor = caller(0);
+
+    if ( @_ and $_[0] eq '-norequire' ) {
+        shift @_;
+    } else {
+        for ( my @filename = @_ ) {
+            if ( $_ eq $inheritor ) {
+                warn "Class '$inheritor' tried to inherit from itself\n";
+            };
+
+            s{::|'}{/}g;
+            require "$_.pm"; # dies if the file is not found
+        }
+    }
+
+    {
+        no strict 'refs';
+        # This is more efficient than push for the new MRO
+        # at least until the new MRO is fixed
+        @{"$inheritor\::ISA"} = (@{"$inheritor\::ISA"} , @_);
+    };
+};
+
+"All your base are belong to us"
+
+__END__
+
+=head1 NAME
+
+parent - Establish an ISA relationship with base classes at compile time
+
+=head1 SYNOPSIS
+
+    package Baz;
+    use parent qw(Foo Bar);
+
+=head1 DESCRIPTION
+
+Allows you to both load one or more modules, while setting up inheritance from
+those modules at the same time.  Mostly similar in effect to
+
+    package Baz;
+    BEGIN {
+        require Foo;
+        require Bar;
+        push @ISA, qw(Foo Bar);
+    }
+
+By default, every base class needs to live in a file of its own.
+If you want to have a subclass and its parent class in the same file, you
+can tell C<parent> not to load any modules by using the C<-norequire> switch:
+
+  package Foo;
+  sub exclaim { "I CAN HAS PERL" }
+
+  package DoesNotLoadFooBar;
+  use parent -norequire, 'Foo', 'Bar';
+  # will not go looking for Foo.pm or Bar.pm
+
+This is equivalent to the following code:
+
+  package Foo;
+  sub exclaim { "I CAN HAS PERL" }
+
+  package DoesNotLoadFooBar;
+  push @DoesNotLoadFooBar::ISA, 'Foo', 'Bar';
+
+This is also helpful for the case where a package lives within
+a differently named file:
+
+  package MyHash;
+  use Tie::Hash;
+  use parent -norequire, 'Tie::StdHash';
+
+This is equivalent to the following code:
+
+  package MyHash;
+  require Tie::Hash;
+  push @ISA, 'Tie::StdHash';
+
+If you want to load a subclass from a file that C<require> would
+not consider an eligible filename (that is, it does not end in
+either C<.pm> or C<.pmc>), use the following code:
+
+  package MySecondPlugin;
+  require './plugins/custom.plugin'; # contains Plugin::Custom
+  use parent -norequire, 'Plugin::Custom';
+
+=head1 DIAGNOSTICS
+
+=over 4
+
+=item Class 'Foo' tried to inherit from itself
+
+Attempting to inherit from yourself generates a warning.
+
+    use Foo;
+    use parent 'Foo';
+
+=back
+
+=head1 HISTORY
+
+This module was forked from L<base> to remove the cruft
+that had accumulated in it.
+
+=head1 CAVEATS
+
+=head1 SEE ALSO
+
+L<base>
+
+=head1 AUTHORS AND CONTRIBUTORS
+
+Rafaël Garcia-Suarez, Bart Lateur, Max Maischein, Anno Siegel, Michael Schwern
+
+=head1 MAINTAINER
+
+Max Maischein C< corion@cpan.org >
+
+Copyright (c) 2007 Max Maischein C<< <corion@cpan.org> >>
+Based on the idea of C<base.pm>, which was introduced with Perl 5.004_04.
+
+=head1 LICENSE
+
+This module is released under the same terms as Perl itself.
+
+=cut