package My::Class;
use strict;
use warnings;
# Generate 3 accessors
use Term::Table::HashBase qw/foo -bar ^baz <bat >ban +boo/;
# Chance to initialize defaults
sub init {
my $self = shift; # No other args
$self->{+FOO} ||= "foo";
$self->{+BAR} ||= "bar";
$self->{+BAZ} ||= "baz";
$self->{+BAT} ||= "bat";
$self->{+BAN} ||= "ban";
$self->{+BOO} ||= "boo";
}
sub print {
print join ", " => map { $self->{$_} } FOO, BAR, BAZ, BAT, BAN, BOO;
}
Subclass it
package My::Subclass;
use strict;
use warnings;
# Note, you should subclass before loading HashBase.
use base 'My::Class';
use Term::Table::HashBase qw/bub/;
sub init {
my $self = shift;
# We get the constants from the base class for free.
$self->{+FOO} ||= 'SubFoo';
$self->{+BUB} ||= 'bub';
$self->SUPER::init();
}
use it:
package main;
use strict;
use warnings;
use My::Class;
# These are all functionally identical
my $one = My::Class->new(foo => 'MyFoo', bar => 'MyBar');
my $two = My::Class->new({foo => 'MyFoo', bar => 'MyBar'});
my $three = My::Class->new(['MyFoo', 'MyBar']);
# Readers!
my $foo = $one->foo; # 'MyFoo'
my $bar = $one->bar; # 'MyBar'
my $baz = $one->baz; # Defaulted to: 'baz'
my $bat = $one->bat; # Defaulted to: 'bat'
# '>ban' means setter only, no reader
# '+boo' means no setter or reader, just the BOO constant
# Setters!
$one->set_foo('A Foo');
#'-bar' means read-only, so the setter will throw an exception (but is defined).
$one->set_bar('A bar');
# '^baz' means deprecated setter, this will warn about the setter being
# deprecated.
$one->set_baz('A Baz');
# '<bat' means no setter defined at all
# '+boo' means no setter or reader, just the BOO constant
$one->{+FOO} = 'xxx';
HashBase will not export "new()" if there is already a "new()" method in your packages inheritance chain.
If you do not want this method you can define your own you just have to declare it before loading Term::Table::HashBase.
package My::Package;
# predeclare new() so that HashBase does not give us one.
sub new;
use Term::Table::HashBase qw/foo bar baz/;
# Now we define our own new method.
sub new { ... }
This makes it so that HashBase sees that you have your own "new()" method. Alternatively you can define the method before loading HashBase instead of just declaring it, but that scatters your use statements.
The most common way to create an object is to pass in key/value pairs where each key is an attribute and each value is what you want assigned to that attribute. No checking is done to verify the attributes or values are valid, you may do that in "init()" if desired.
If you would like, you can pass in a hashref instead of pairs. When you do so the hashref will be copied, and the copy will be returned blessed as an object. There is no way to ask HashBase to bless a specific hashref.
In some cases an object may only have 1 or 2 attributes, in which case a hashref may be too verbose for your liking. In these cases you can pass in an arrayref with only values. The values will be assigned to attributes in the order the attributes were listed. When there is inheritance involved the attributes from parent classes will come before subclasses.
Note: Term::Table::HashBase checks for an init using "$class->can('init')" during construction. It DOES NOT call "can()" on the created object. Also note that the result of the check is cached, it is only ever checked once, the first time an instance of your class is created. This means that adding an "init()" method AFTER the first construction will result in it being ignored.
use Term::Table::HashBase qw/foo/;
This will generate the following subs in your namespace:
The main reason for using these constants is to help avoid spelling mistakes and similar typos. It will not help you if you forget to prefix the '+' though.
use Term::Table::HashBase qw/-foo/;
use Term::Table::HashBase qw/^foo/;
use Term::Table::HashBase qw/<foo/;
Only gives you a reader, no "set_foo" method is defined at all.
use Term::Table::HashBase qw/>foo/;
Only gives you a write ("set_foo"), no "foo" method is defined at all.
use Term::Table::HashBase qw/+foo/;
This does not create any methods for you, it just adds the "FOO" constant.
use base 'Another::HashBase::Class';
use Term::Table::HashBase qw/foo bar baz/;
The base class is added to @ISA for you, and all constants from base classes are added to subclasses automatically.
Note: This list is used in the "$class->new(\@ARRAY)" constructor to determine the attribute to which each value will be paired.
This program is free software; you can redistribute it and/or modify it under the same terms as Perl itself.
See http://dev.perl.org/licenses/