class::fields::fuxor(3)

NAME

Class::Fields::Fuxor - Low level manipuation of object

data members

SYNOPSIS

# As functions.
use Class::Fields::Fuxor;
add_fields($class, $attrib, @fields);
add_field_set($class, @fields, @attribs);
has_fields($class);
$fields = get_fields($class);
$fattr  = get_attr($class);
# As methods.
package Foo;
use base qw( Class::Fields::Fuxor );
Foo->add_fields($attrib, @fields);
Foo->has_fields;
$fields   = Foo->get_fields;
$fattr    = Foo->get_attr;

DESCRIPTION

This is a module for low level manipuation of the %FIELDS
hash and its accompying %fields::attr hash without actu
ally touching them. Modules like fields.pm, base.pm and
public.pm make use of this module.

%FIELDS and %fields::attr are currently used to store
information about the data members of classes. Since the
current data inheritance system, built around
pseudo-hashes, is considered a bit twitchy, it is wise to
encapsulate and rope it off in the expectation that it
will be replaced with something better.

Typically one does not want to mess with this stuff and
instead uses fields.pm and friends or perhaps
Class::Fields.

add_fields

add_fields($class, $attrib, @fields);

Adds a bunch of @fields to the given $class using the
given $attrib. For example:

# Add the public fields 'this' and 'that' to the

class Foo.
use Class::Fields::Attribs;
add_fields('Foo', PUBLIC, qw(this that));

$attrib is built from the constants in
Class::Fields::Attribs

add_field_set

add_field_set($class, @fields, @attribs);

Functionally similar to add_fields(), excepting that it can add a group of fields with different attributes
all at once. This is necessary for the proper func
tioning of fields.pm.

Each element in @fields matches up with one in
@attribs. Obviously, the two arrays must be the same
size.

has_fields

has_fields($class);

A simple check to see if the given $class has a
%FIELDS hash defined. A simple test like (defined
%{"$class:FIELDS"}) will sometimes produce typo
warnings because it would create the hash if it was
not present before.

get_attr

$fattr = get_attr($class);

Get's the field attribute array for the given $class.
This is roughly equivalent to $fields::attr{$class}
but we put a nice wrapper around it for compatibility
and readability.

$fattr is an array reference containing the attributes
of the fields in the given $class. Each entry in
$fattr corresponds to the position indicated by the
$class's %FIELDS has. For example:

package Foo;
use fields qw(this _that);

$fattr = get_attr('Foo');

# Get the attributes for '_that' in the class

'Foo'.
$that_attribs = print $fat

tr->[$Foo::FIELDS->{_that}];

When possible, one should avoid using this function
since it exposes more implementation detail than I'd
like. Class::Fields should provide most of the func
tionality you'll need.

get_fields

$fields = get_fields($class);

Gets a reference to the %FIELDS hash for the given
$class. It will autogenerate a %FIELDS hash if one
doesn't already exist. If you don't want this behav
ior, be sure to check beforehand with has_fields().

When possible, one should avoid using this function
since it exposes more implementation detail than I'd
like. Class::Fields should provide most of the func
tionality you'll need.

AUTHOR

Michael G Schwern <schwern@pobox.com> based heavily on
code liberated from the original fields.pm and base.pm.

SEE ALSO

fields, base, public, private, protected, Class::Fields,
Class::Fields::Attribs

perl v5.8.0 2000-07-16 Class::Fields::Fuxor(3)