package Hash::WithDefaults;
use strict;
use Carp;
require Tie::Hash;
use vars qw(@ISA $VERSION);
@ISA = qw(Tie::StdHash);
$VERSION = '0.04';
sub DATA () {0}
sub DEFAULTS () {1}
sub ACTDEFAULT () {2}
sub SEEN () {3}
sub makeTIEHASH {
my ($class, $set) = @_;
$class = 'Hash::WithDefaults::' . $class;
eval "sub ${class}::TIEHASH {" . <<'*END*' . "\t\t\t" . $set . <<'*END*' . "\t\t\t" . $set . <<'*END*';
my $class = shift();
my $data = {};
if (! @_) {
# no parameters
return bless [ $data, []], $class;
}
if (@_ == 1 and ref $_[0] eq 'HASH') {
my $input=$_[0];
my ($key,$value);
while (($key,$value) = each(%$input)) {
*END*
}
} else {
my ($i, $arr) = (0);
if (ref $_[0] eq 'ARRAY') {
$arr = $_[0];
} elsif (@_ % 2 == 0) {
$arr = \@_;
} else {
croak "Ussage: tie %hashname, $class, \%hash\n or tie %hashname, $class, \\\%hash\n or tie %hashname, $class, \\\@array\n";
}
while ($i <= $#$arr) {
my ($key,$value)=($arr->[$i],$arr->[$i+1]); $i+=2;
*END*
}
}
bless [$data, []];
}
*END*
}
makeTIEHASH 'sensitive', '$data->{$key} = $value;';
makeTIEHASH 'tolower', '$data->{lc $key} = $value;';
makeTIEHASH 'toupper', '$data->{uc $key} = $value;';
makeTIEHASH 'lower', '$data->{lc $key} = $value;';
makeTIEHASH 'upper', '$data->{uc $key} = $value;';
makeTIEHASH 'preserve', '$data->{lc $key} = [$key,$value];';
sub TIEHASH {
shift(); # shift out class name
if (@_ == 0) {
# no parameters
unshift @_, 'Hash::WithDefaults::preserve';
goto &Hash::WithDefaults::preserve::TIEHASH;
}
if (!ref $_[0] and (ref $_[1] eq 'HASH' or @_ % 2 == 1)) {
# type plus either \%hash or %hash
my $type = lc(splice(@_, 0, 1));
if ($type =~ /^(?:sensitive|preserve|lower|upper|tolower|toupper)$/) {
unshift @_, 'Hash::WithDefaults::' . $type;
no strict 'refs';
goto &{"Hash::WithDefaults::".$type."::TIEHASH"};
} else {
croak "Unknown type '$type'! Use one of:\n\tsensitive, preserve, lower, upper, tolower, toupper";
}
} else {
unshift @_, 'Hash::WithDefaults::preserve';
goto &Hash::WithDefaults::preserve::TIEHASH;
}
}
sub AddDefault {
push @{$_[0]->[DEFAULTS]}, $_[1];
return 1;
}
sub GetDefaults {
my $self = shift;
return $self->[DEFAULTS];
}
sub CLEAR {
my $self = shift;
undef $self->[SEEN];
undef $self->[ACTDEFAULT];
$self
}
#############################
package Hash::WithDefaults::preserve;
BEGIN {*Hash::WithDefaults::Preserve:: = \%Hash::WithDefaults::preserve::;}
@Hash::WithDefaults::preserve::ISA = qw(Hash::WithDefaults);
sub DATA () {0}
sub DEFAULTS () {1}
sub ACTDEFAULT () {2}
sub SEEN () {3}
sub TIEHASH {
splice( @_, 1, 0, 'preserve');
goto &Hash::WithDefaults::TIEHASH;
}
sub STORE {
$_[0]->[DATA]->{lc $_[1]} = [$_[1],$_[2]];
}
sub FETCH {
my $lc_key = lc $_[1];
return ${$_[0]->[DATA]->{$lc_key}}[1]
if exists $_[0]->[DATA]->{$lc_key};
foreach my $default (@{$_[0]->[DEFAULTS]}) {
return $default->{$_[1]}
if exists($default->{$_[1]});
}
return;
}
sub EXISTS {
return 1
if exists $_[0]->[DATA]->{lc $_[1]};
foreach my $default (@{$_[0]->[DEFAULTS]}) {
return 1
if exists($default->{$_[1]});
}
return;
}
sub DELETE {
delete $_[0]->[DATA]->{lc $_[1]}
}
sub FIRSTKEY {
my $self = $_[0];
undef $self->[ACTDEFAULT];
$self->[SEEN] = {};
keys %{$self->[DATA]};
my ($key,$val);
if (($key,$val) = each %{$self->[DATA]}) {
$self->[SEEN]->{$key}=1;
return wantarray ? ($val->[0], $val->[1]) : $val->[0];
} elsif (@{$self->[DEFAULTS]}) {
return $self->NEXTKEY();
} else {
return;
}
}
sub NEXTKEY {
my $self = $_[0];
my $seen = $self->[SEEN];
my ($key,$val);
if (!defined $self->[ACTDEFAULT]) {
# processing the base hash
if (($key,$val) = each %{$self->[DATA]}) {
$seen->{$key}=1;
return wantarray ? ($val->[0], $val->[1]) : $val->[0];
} else {
# base hash done
if (! @{$self->[DEFAULTS]}) {
# no defaults
return;
} else {
$self->[ACTDEFAULT]=0;
# reset the first default
keys %{$self->[DEFAULTS]->[0]};
}
}
}
while (exists $self->[DEFAULTS]->[$self->[ACTDEFAULT]]) {
while (($key,$val) = each %{$self->[DEFAULTS]->[$self->[ACTDEFAULT]]}) {
return wantarray ? ($key, $val) : $key
unless $seen->{lc $key}++;
}
$self->[ACTDEFAULT]++;
keys %{$self->[DEFAULTS]->[$self->[ACTDEFAULT]]}
if exists $self->[DEFAULTS]->[$self->[ACTDEFAULT]];
}
# all hashes done. Cleanup
undef $self->[SEEN];
undef $self->[ACTDEFAULT];
return;
}
#############################
package Hash::WithDefaults::lower;
BEGIN {*Hash::WithDefaults::Lower:: = \%Hash::WithDefaults::lower::;}
@Hash::WithDefaults::lower::ISA = qw(Hash::WithDefaults::preserve);
sub DATA () {0}
sub DEFAULTS () {1}
sub ACTDEFAULT () {2}
sub SEEN () {3}
sub TIEHASH {
splice( @_, 1, 0, 'lower');
goto &Hash::WithDefaults::TIEHASH;
}
sub STORE {
$_[0]->[DATA]->{lc $_[1]} = $_[2];
}
sub FETCH {
return $_[0]->[DATA]->{lc $_[1]}
if exists $_[0]->[DATA]->{lc $_[1]};
foreach my $default (@{$_[0]->[DEFAULTS]}) {
return $default->{$_[1]}
if exists($default->{$_[1]});
}
return;
}
sub EXISTS {
return 1
if exists $_[0]->[DATA]->{lc $_[1]};
foreach my $default (@{$_[0]->[DEFAULTS]}) {
return 1
if exists($default->{$_[1]});
}
return;
}
sub DELETE {
delete $_[0]->[DATA]->{lc $_[1]}
}
sub FIRSTKEY {
my $self = $_[0];
$self->[ACTDEFAULT] = -1;
$self->[SEEN] = {};
keys %{$self->[DATA]};
my ($key,$val);
if (($key,$val) = each %{$self->[DATA]}) {
$self->[SEEN]->{$key}=1;
return wantarray ? ($key, $val) : $key;
} elsif (@{$self->[DEFAULTS]}) {
return $self->NEXTKEY();
} else {
return;
}
}
sub NEXTKEY {
my $self = $_[0];
my $seen = $self->[SEEN];
my $defaults = $self->[DEFAULTS];
my ($key,$val);
if ($self->[ACTDEFAULT] == -1) {
# processing the base hash
if (($key,$val) = each %{$self->[DATA]}) {
$seen->{$key}=1;
return wantarray ? ($key, $val) : $key;
} else {
# base hash done
$self->[ACTDEFAULT]=0;
if (! @$defaults) {
# no defaults
return;
} else {
# reset the first default
keys %{$defaults->[0]};
}
}
}
while (exists $defaults->[$self->[ACTDEFAULT]]) {
while (($key,$val) = each %{$defaults->[$self->[ACTDEFAULT]]}) {
return wantarray ? ($key, $val) : $key
unless $seen->{lc $key}++;
}
$self->[ACTDEFAULT]++;
keys %{$defaults->[$self->[ACTDEFAULT]]}
if exists $defaults->[$self->[ACTDEFAULT]];
}
# all hashes done. Cleanup
undef $self->[SEEN];
undef $self->[ACTDEFAULT];
return;
}
#############################
package Hash::WithDefaults::upper;
BEGIN {*Hash::WithDefaults::Upper:: = \%Hash::WithDefaults::upper::;}
@Hash::WithDefaults::upper::ISA = qw(Hash::WithDefaults::preserve);
sub DATA () {0}
sub DEFAULTS () {1}
sub ACTDEFAULT () {2}
sub SEEN () {3}
sub TIEHASH {
splice( @_, 1, 0, 'upper');
goto &Hash::WithDefaults::TIEHASH;
}
sub STORE {
$_[0]->[DATA]->{uc $_[1]} = $_[2];
}
sub FETCH {
return $_[0]->[DATA]->{uc $_[1]}
if exists $_[0]->[DATA]->{uc $_[1]};
foreach my $default (@{$_[0]->[DEFAULTS]}) {
return $default->{$_[1]}
if exists($default->{$_[1]});
}
return;
}
sub EXISTS {
return 1
if exists $_[0]->[DATA]->{uc $_[1]};
foreach my $default (@{$_[0]->[DEFAULTS]}) {
return 1
if exists($default->{$_[1]});
}
return;
}
sub DELETE {
delete $_[0]->[DATA]->{uc $_[1]}
}
sub FIRSTKEY {
my $self = $_[0];
$self->[ACTDEFAULT] = -1;
$self->[SEEN] = {};
keys %{$self->[DATA]};
my ($key,$val);
if (($key,$val) = each %{$self->[DATA]}) {
$self->[SEEN]->{$key}=1;
return wantarray ? ($key, $val) : $key;
} elsif (@{$self->[DEFAULTS]}) {
return $self->NEXTKEY();
} else {
return;
}
}
sub NEXTKEY {
my $self = $_[0];
my $seen = $self->[SEEN];
my $defaults = $self->[DEFAULTS];
my ($key,$val);
if ($self->[ACTDEFAULT] == -1) {
# processing the base hash
if (($key,$val) = each %{$self->[DATA]}) {
$seen->{$key}=1;
return wantarray ? ($key, $val) : $key;
} else {
# base hash done
$self->[ACTDEFAULT]=0;
if (! @$defaults) {
# no defaults
return;
} else {
# reset the first default
keys %{$defaults->[0]};
}
}
}
while (exists $defaults->[$self->[ACTDEFAULT]]) {
while (($key,$val) = each %{$defaults->[$self->[ACTDEFAULT]]}) {
return wantarray ? ($key, $val) : $key
unless $seen->{uc $key}++;
}
$self->[ACTDEFAULT]++;
keys %{$defaults->[$self->[ACTDEFAULT]]}
if exists $defaults->[$self->[ACTDEFAULT]];
}
# all hashes done. Cleanup
undef $self->[SEEN];
undef $self->[ACTDEFAULT];
return;
}
#############################
package Hash::WithDefaults::sensitive;
BEGIN {*Hash::WithDefaults::Sensitive:: = \%Hash::WithDefaults::sensitive::;}
@Hash::WithDefaults::sensitive::ISA = qw(Hash::WithDefaults);
sub DATA () {0}
sub DEFAULTS () {1}
sub ACTDEFAULT () {2}
sub SEEN () {3}
sub TIEHASH {
splice( @_, 1, 0, 'sensitive');
goto &Hash::WithDefaults::TIEHASH;
}
sub STORE {
$_[0]->[DATA]->{$_[1]} = $_[2];
}
sub FETCH {
return $_[0]->[DATA]->{$_[1]}
if exists $_[0]->[DATA]->{$_[1]};
foreach my $default (@{$_[0]->[DEFAULTS]}) {
return $default->{$_[1]}
if exists($default->{$_[1]});
}
return;
}
sub EXISTS {
return 1
if exists $_[0]->[DATA]->{$_[1]};
foreach my $default (@{$_[0]->[DEFAULTS]}) {
return 1
if exists($default->{$_[1]});
}
return;
}
sub DELETE {
delete $_[0]->[DATA]->{$_[1]}
}
sub FIRSTKEY {
my $self = $_[0];
$self->[ACTDEFAULT] = -1;
$self->[SEEN] = {};
keys %{$self->[DATA]};
my ($key,$val);
if (($key,$val) = each %{$self->[DATA]}) {
$self->[SEEN]->{$key}=1;
return wantarray ? ($key, $val) : $key;
} elsif (@{$self->[DEFAULTS]}) {
return $self->NEXTKEY();
} else {
return;
}
}
sub NEXTKEY {
my $self = $_[0];
my $seen = $self->[SEEN];
my $defaults = $self->[DEFAULTS];
my ($key,$val);
if ($self->[ACTDEFAULT] == -1) {
# processing the base hash
if (($key,$val) = each %{$self->[DATA]}) {
$seen->{$key}=1;
return wantarray ? ($key, $val) : $key;
} else {
# base hash done
$self->[ACTDEFAULT]=0;
if (! @$defaults) {
# no defaults
return;
} else {
# reset the first default
keys %{$defaults->[0]};
}
}
}
while (exists $defaults->[$self->[ACTDEFAULT]]) {
while (($key,$val) = each %{$defaults->[$self->[ACTDEFAULT]]}) {
return wantarray ? ($key, $val) : $key
unless $seen->{$key}++;
}
$self->[ACTDEFAULT]++;
keys %{$defaults->[$self->[ACTDEFAULT]]}
if exists $defaults->[$self->[ACTDEFAULT]];
}
# all hashes done. Cleanup
undef $self->[SEEN];
undef $self->[ACTDEFAULT];
return;
}
#############################
package Hash::WithDefaults::toupper;
BEGIN {*Hash::WithDefaults::Toupper:: = \%Hash::WithDefaults::toupper::;}
@Hash::WithDefaults::toupper::ISA = qw(Hash::WithDefaults::sensitive);
sub DATA () {0}
sub DEFAULTS () {1}
sub ACTDEFAULT () {2}
sub SEEN () {3}
sub TIEHASH {
splice( @_, 1, 0, 'toupper');
goto &Hash::WithDefaults::TIEHASH;
}
sub STORE {
$_[0]->[DATA]->{uc $_[1]} = $_[2];
}
#############################
package Hash::WithDefaults::tolower;
BEGIN {*Hash::WithDefaults::Tolower:: = \%Hash::WithDefaults::tolower::;}
@Hash::WithDefaults::tolower::ISA = qw(Hash::WithDefaults::sensitive);
sub DATA () {0}
sub DEFAULTS () {1}
sub ACTDEFAULT () {2}
sub SEEN () {3}
sub TIEHASH {
splice( @_, 1, 0, 'tolower');
goto &Hash::WithDefaults::TIEHASH;
}
sub STORE {
$_[0]->[DATA]->{lc $_[1]} = $_[2];
}
1;
__END__
=head1 NAME
Hash::WithDefaults - class for hashes with key-casing requirements supporting defaults
version 0.04
=head1 SYNOPSIS
use Hash::WithDefaults;
%main = ( ... );
tie %h1, 'Hash::WithDefaults', {...};
tied(%h1)->AddDefault(\%main);
tie %h2, 'Hash::WithDefaults', {...};
tied(%h2)->AddDefault(\%main);
# now if you use $h1{$key}, the value is looked up first
# in %h1, then in %main.
=head1 DESCRIPTION
This module implements hashes that support "defaults". That is you may specify
several more hashes in which the data will be looked up in case it is not found in
the current hash.
=head2 Object creation
tie %hash, 'Hash::WithDefault', [$case_option], [\%values];
tie %hash, 'Hash::WithDefault', [$case_option], [%values];
The optional $case_option may be one of these values:
Sensitive - the hash will be case sensitive
Tolower - the hash will be case sensitive, all keys are made lowercase
Toupper - the hash will be case sensitive, all keys are made uppercase
Preserve - the hash will be case insensitive, the case is preserved
Lower - the hash will be case insensitive, all keys are made lowercase
Upper - the hash will be case insensitive, all keys are made uppercase
If you pass a hash reference or an even list of keys and values to the tie() function,
those keys and values will be COPIED to the resulting magical hash!
After you tie() the hash, you use it just like any other hash.
=head2 Functions
=head3 AddDefault
tied(%hash)->AddDefault(\%defaults);
This instructs the object to include the %defaults in the search for values.
After this the value will be looked up first in %hash itself and then in %defaults.
You may keep modifying the %defaults and your changes WILL be visible through %hash!
You may add as many defaults to one Hash::WithDefaults object as you like.
=head3 GetDefaults
$defaults = tied(%hash)->GetDefaults();
push @$defaults, \%another_default;
Returns a reference to the array that stores the defaults.
You may delete or insert hash references into the array, but make sure you
NEVER EVER insert anything else than a hash reference into the array!
=head2 Config::IniHash example
use Config::IniHash;
$config = ReadIni $inifile, withdefaults => 1, insensitive => 'preserve';
if (exists $config->{':default'}) {
my $default = $config->{':default'};
foreach my $section (keys %$config) {
next if $section =~ /^:/;
tied(%{$config->{$section}})->AddDefault($default)
}
}
And now all normal sections will get the default values from [:default] section ;-)
=head1 AUTHOR
Jan Krynicky <Jenda@Krynicky.cz>
http://Jenda.Krynicky.cz
=head1 COPYRIGHT
Copyright (c) 2002 Jan Krynicky <Jenda@Krynicky.cz>. All rights reserved.
This program is free software; you can redistribute it and/or
modify it under the same terms as Perl itself.
=cut