-package TieHash;
+package Tie::Hash;
+
+our $VERSION = '1.00';
=head1 NAME
-TieHash, TieHash::Std - base class definitions for tied hashes
+Tie::Hash, Tie::StdHash - base class definitions for tied hashes
=head1 SYNOPSIS
package NewHash;
- require TieHash;
-
- @ISA = (TieHash);
-
+ require Tie::Hash;
+
+ @ISA = (Tie::Hash);
+
sub DELETE { ... } # Provides needed method
sub CLEAR { ... } # Overrides inherited method
-
-
+
+
package NewStdHash;
- require TieHash;
-
- @ISA = (TieHash::Std);
-
+ require Tie::Hash;
+
+ @ISA = (Tie::StdHash);
+
# All methods provided by default, define only those needing overrides
sub DELETE { ... }
-
-
+
+
package main;
-
- tie %new_hash, NewHash;
- tie %new_std_hash, NewStdHash;
+
+ tie %new_hash, 'NewHash';
+ tie %new_std_hash, 'NewStdHash';
=head1 DESCRIPTION
This module provides some skeletal methods for hash-tying classes. See
-L<perlfunc/tie> for a list of the functions required in order to tie a hash
-to a package. The basic B<TieHash> package provides a C<new> method, as well
-as methods C<TIEHASH>, C<EXISTS> and C<CLEAR>. The B<TieHash::Std> package
-provides most methods required for hashes in L<perlfunc/tie>. It inherits from
-B<TieHash>, and causes tied hashes to behave exactly like standard hashes,
-allowing for selective overloading of methods. The B<new> method is provided
-as grandfathering in the case a class forgets to include a B<TIEHASH> method.
+L<perltie> for a list of the functions required in order to tie a hash
+to a package. The basic B<Tie::Hash> package provides a C<new> method, as well
+as methods C<TIEHASH>, C<EXISTS> and C<CLEAR>. The B<Tie::StdHash> package
+provides most methods required for hashes in L<perltie>. It inherits from
+B<Tie::Hash>, and causes tied hashes to behave exactly like standard hashes,
+allowing for selective overloading of methods. The C<new> method is provided
+as grandfathering in the case a class forgets to include a C<TIEHASH> method.
For developers wishing to write their own tied hashes, the required methods
-are:
+are briefly defined below. See the L<perltie> section for more detailed
+descriptive, as well as example code:
+
+=over 4
=item TIEHASH classname, LIST
-The method invoked by the command C<tie %hash, class>. Associates a new
+The method invoked by the command C<tie %hash, classname>. Associates a new
hash instance with the specified class. C<LIST> would represent additional
arguments (along the lines of L<AnyDBM_File> and compatriots) needed to
complete the association.
=item FIRSTKEY this
-Return the (key, value) pair for the first key in the hash.
+Return the first key in the hash.
=item NEXTKEY this, lastkey
-Return the next (key, value) pair for the hash.
+Return the next key in the hash.
=item EXISTS this, key
Verify that I<key> exists with the tied hash I<this>.
+The B<Tie::Hash> implementation is a stub that simply croaks.
+
=item DELETE this, key
Delete the key I<key> from the tied hash I<this>.
=head1 CAVEATS
-The L<perlfunc/tie> documentation includes a method called C<DESTROY> as
-a necessary method for tied hashes. Neither B<TieHash> nor B<TieHash::Std>
-define a default for this method.
-
-The C<CLEAR> method provided by these two packages is not listed in the
-L<perlfunc/tie> section.
+The L<perltie> documentation includes a method called C<DESTROY> as
+a necessary method for tied hashes. Neither B<Tie::Hash> nor B<Tie::StdHash>
+define a default for this method. This is a standard for class packages,
+but may be omitted in favor of a simple default.
=head1 MORE INFORMATION
-The packages relating to various DBM-related implemetations (F<DB_File>,
+The packages relating to various DBM-related implementations (F<DB_File>,
F<NDBM_File>, etc.) show examples of general tied hashes, as does the
-L<Config> module. While these do not utilize B<TieHash>, they serve as
+L<Config> module. While these do not utilize B<Tie::Hash>, they serve as
good working examples.
=cut
-
+
use Carp;
+use warnings::register;
sub new {
my $pkg = shift;
sub TIEHASH {
my $pkg = shift;
- if (defined &{"{$pkg}::new"}) {
- carp "WARNING: calling ${pkg}->new since ${pkg}->TIEHASH is missing"
- if $^W;
+ if (defined &{"${pkg}::new"}) {
+ warnings::warnif("WARNING: calling ${pkg}->new since ${pkg}->TIEHASH is missing");
$pkg->new(@_);
}
else {
}
}
-# The TieHash::Std package implements standard perl hash behaviour.
+# The Tie::StdHash package implements standard perl hash behaviour.
# It exists to act as a base class for classes which only wish to
# alter some parts of their behaviour.
-package TieHash::Std;
-@ISA = qw(TieHash);
+package Tie::StdHash;
+@ISA = qw(Tie::Hash);
sub TIEHASH { bless {}, $_[0] }
sub STORE { $_[0]->{$_[1]} = $_[2] }
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