Attribute::Property $Id: README,v 1.3 2003/02/09 19:04:50 juerd Exp $ INSTALLATION To install this module type the following: perl Makefile.PL make make test make install Or use CPANPLUS to automate the process. Module documentation: NAME Attribute::Property - Easy lvalue accessors with validation. ($foo->bar = 42) SYNOPSIS CLASS package SomeClass; use Attribute::Property; use Carp; sub new { bless { }, shift } sub nondigits : Property { /^\D+\z/ } sub digits : Property { /^\d+\z/ or croak "custom error message" } sub anyvalue : Property; sub another : Property; sub value : Property { my $self = shift; # Object is accessible as $_[0] s/^\s+//; # New value can be altered through $_ or $_[1] $_ <= $self->maximum or croak "Value exceeds maximum"; } USAGE my $object = SomeClass->new; $object->nondigits = "abc"; $object->digits = "123"; $object->anyvalue = "abc123\n"; $object->anyvalue('archaic style still works'); # These would croak $object->nondigits = "987"; $object->digits = "xyz"; DESCRIPTION This module introduces the "Property" attribute, which turns your method into an object property. The original code block is used only to validate new values, the module croaks if it returns false. Feel free to croak explicitly if you don't want the default error message. Undefined subs (subs that have been declared but do not have a code block) with the "Property" attribute will be properties without any validation. In the validation code block, the object is in $_[0] and the value to be validated is aliased as $_[1] and for regexing convenience as $_. PREREQUISITES Your object must be a blessed hash reference. The property names will be used for the hash keys. For class properties of "Some::Module", the hash %Some::Module is used, for class properties of "Module", the hash %Attribute::Property::Module is used. In short: "$foo->bar = 14" and "$foo->bar(14)" assign 14 to "$foo->{bar}" after positive validation. COMPATIBILITY Old fashioned "$object->property(VALUE)" is still available. This module requires a modern Perl, fossils like Perl 5.00x don't support our chicanery. LICENSE There is no license. This software was released into the public domain. Do with it what you want, but on your own risk. Both authors disclaim any responsibility. AUTHORS Juerd Waalboer Matthijs van Duin