.\" Automatically generated by Pod::Man 2.28 (Pod::Simple 3.29) .\" .\" Standard preamble: .\" ======================================================================== .de Sp \" Vertical space (when we can't use .PP) .if t .sp .5v .if n .sp .. .de Vb \" Begin verbatim text .ft CW .nf .ne \\$1 .. .de Ve \" End verbatim text .ft R .fi .. .\" Set up some character translations and predefined strings. \*(-- will .\" give an unbreakable dash, \*(PI will give pi, \*(L" will give a left .\" double quote, and \*(R" will give a right double quote. \*(C+ will .\" give a nicer C++. Capital omega is used to do unbreakable dashes and .\" therefore won't be available. \*(C` and \*(C' expand to `' in nroff, .\" nothing in troff, for use with C<>. .tr \(*W- .ds C+ C\v'-.1v'\h'-1p'\s-2+\h'-1p'+\s0\v'.1v'\h'-1p' .ie n \{\ . ds -- \(*W- . ds PI pi . if (\n(.H=4u)&(1m=24u) .ds -- \(*W\h'-12u'\(*W\h'-12u'-\" diablo 10 pitch . if (\n(.H=4u)&(1m=20u) .ds -- \(*W\h'-12u'\(*W\h'-8u'-\" diablo 12 pitch . ds L" "" . ds R" "" . ds C` "" . ds C' "" 'br\} .el\{\ . ds -- \|\(em\| . ds PI \(*p . ds L" `` . ds R" '' . ds C` . ds C' 'br\} .\" .\" Escape single quotes in literal strings from groff's Unicode transform. .ie \n(.g .ds Aq \(aq .el .ds Aq ' .\" .\" If the F register is turned on, we'll generate index entries on stderr for .\" titles (.TH), headers (.SH), subsections (.SS), items (.Ip), and index .\" entries marked with X<> in POD. Of course, you'll have to process the .\" output yourself in some meaningful fashion. .\" .\" Avoid warning from groff about undefined register 'F'. .de IX .. .nr rF 0 .if \n(.g .if rF .nr rF 1 .if (\n(rF:(\n(.g==0)) \{ . if \nF \{ . de IX . tm Index:\\$1\t\\n%\t"\\$2" .. . if !\nF==2 \{ . nr % 0 . nr F 2 . \} . \} .\} .rr rF .\" ======================================================================== .\" .IX Title "MakeMethods::Emulator::Inheritable 3pm" .TH MakeMethods::Emulator::Inheritable 3pm "2016-06-10" "perl v5.22.2" "User Contributed Perl Documentation" .\" For nroff, turn off justification. Always turn off hyphenation; it makes .\" way too many mistakes in technical documents. .if n .ad l .nh .SH "NAME" Class::MakeMethods::Emulator::Inheritable \- Emulate Class::Inheritable .SH "SYNOPSIS" .IX Header "SYNOPSIS" .Vb 2 \& package Stuff; \& use base qw(Class::MakeMethods::Emulator::Inheritable); \& \& # Set up DataFile as inheritable class data. \& Stuff\->mk_classdata(\*(AqDataFile\*(Aq); \& \& # Declare the location of the data file for this class. \& Stuff\->DataFile(\*(Aq/etc/stuff/data\*(Aq); .Ve .SH "DESCRIPTION" .IX Header "DESCRIPTION" This module is an adaptor that provides emulatation of Class::Data::Inheritable by invoking similar functionality provided by Class::MakeMethods::ClassInherit. .PP The public interface provided by Class::MakeMethods::Emulator::Inheritable is identical to that of Class::Data::Inheritable. .PP Class::Data::Inheritable is for creating accessor/mutators to class data. That is, if you want to store something about your class as a whole (instead of about a single object). This data is then inherited by your subclasses and can be overridden. .SH "USAGE" .IX Header "USAGE" As specified by Class::Data::Inheritable, clients should inherit from this module and then invoke the \fImk_classdata()\fR method for each class method desired: .PP .Vb 1 \& Class\->mk_classdata($data_accessor_name); .Ve .PP This is a class method used to declare new class data accessors. A new accessor will be created in the Class using the name from \&\f(CW$data_accessor_name\fR. .PP .Vb 1 \& Class\->mk_classdata($data_accessor_name, $initial_value); .Ve .PP You may also pass a second argument to initialize the value. .PP To facilitate overriding, mk_classdata creates an alias to the accessor, \fI_field_accessor()\fR. So \fISuitcase()\fR would have an alias \&\fI_Suitcase_accessor()\fR that does the exact same thing as \fISuitcase()\fR. This is useful if you want to alter the behavior of a single accessor yet still get the benefits of inheritable class data. For example. .PP .Vb 3 \& sub Suitcase { \& my($self) = shift; \& warn "Fashion tragedy" if @_ and $_[0] eq \*(AqPlaid\*(Aq; \& \& $self\->_Suitcase_accessor(@_); \& } .Ve .SH "COMPATIBILITY" .IX Header "COMPATIBILITY" Note that the internal implementation of Class::MakeMethods::ClassInherit does not match that of Class::Data::Inheritable. In particular, Class::Data::Inheritable installs new methods in subclasses when they first initialize their value, while .SH "EXAMPLE" .IX Header "EXAMPLE" The example provided by Class::Data::Inheritable is equally applicable to this emulator. .PP .Vb 3 \& package Pere::Ubu; \& use base qw(Class::MakeMethods::Emulator::Inheritable); \& Pere::Ubu\->mk_classdata(\*(AqSuitcase\*(Aq); .Ve .PP will generate the method \fISuitcase()\fR in the class Pere::Ubu. .PP This new method can be used to get and set a piece of class data. .PP .Vb 2 \& Pere::Ubu\->Suitcase(\*(AqRed\*(Aq); \& $suitcase = Pere::Ubu\->Suitcase; .Ve .PP The interesting part happens when a class inherits from Pere::Ubu: .PP .Vb 2 \& package Raygun; \& use base qw(Pere::Ubu); \& \& # Raygun\*(Aqs suitcase is Red. \& $suitcase = Raygun\->Suitcase; .Ve .PP Raygun inherits its Suitcase class data from Pere::Ubu. .PP Inheritance of class data works analgous to method inheritance. As long as Raygun does not \*(L"override\*(R" its inherited class data (by using \&\fISuitcase()\fR to set a new value) it will continue to use whatever is set in Pere::Ubu and inherit further changes: .PP .Vb 2 \& # Both Raygun\*(Aqs and Pere::Ubu\*(Aqs suitcases are now Blue \& Pere::Ubu\->Suitcase(\*(AqBlue\*(Aq); .Ve .PP However, should Raygun decide to set its own \fISuitcase()\fR it has now \&\*(L"overridden\*(R" Pere::Ubu and is on its own, just like if it had overridden a method: .PP .Vb 2 \& # Raygun has an orange suitcase, Pere::Ubu\*(Aqs is still Blue. \& Raygun\->Suitcase(\*(AqOrange\*(Aq); .Ve .PP Now that Raygun has overridden Pere::Ubu futher changes by Pere::Ubu no longer effect Raygun. .PP .Vb 2 \& # Raygun still has an orange suitcase, but Pere::Ubu is using Samsonite. \& Pere::Ubu\->Suitcase(\*(AqSamsonite\*(Aq); .Ve .SH "SEE ALSO" .IX Header "SEE ALSO" See Class::MakeMethods for general information about this distribution. .PP See Class::MakeMethods::Emulator for more about this family of subclasses. .PP See Class::Data::Inheritable for documentation of the original module. .PP See perltootc for a discussion of class data in Perl. .PP See Class::MakeMethods::Standard::Inheritable and Class::MakeMethods::Template::ClassInherit for inheritable data methods.