.\" Automatically generated by Pod::Man 4.09 (Pod::Simple 3.35) .\" .\" 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 >0, 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 .. .if !\nF .nr F 0 .if \nF>0 \{\ . de IX . tm Index:\\$1\t\\n%\t"\\$2" .. . if !\nF==2 \{\ . nr % 0 . nr F 2 . \} .\} .\" ======================================================================== .\" .IX Title "MixinFactory 3pm" .TH MixinFactory 3pm "2017-11-13" "perl v5.26.1" "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::MixinFactory \- Class Factory with Selection of Mixins .SH "SYNOPSIS" .IX Header "SYNOPSIS" .Vb 4 \& package MyClass; \& use Class::MixinFactory \-hasafactory; \& sub new { ... } \& sub foo { return "Foo Bar" } \& \& package MyClass::Logging; \& sub foo { warn "Calling foo"; (shift)\->NEXT(\*(Aqfoo\*(Aq, @_) } \& \& package MyClass::UpperCase; \& sub foo { uc( (shift)\->NEXT(\*(Aqfoo\*(Aq, @_) ) } \& \& package main; \& \& my $class = MyClass\->class( \*(AqLogging\*(Aq, \*(AqUpperCase\*(Aq ); \& print $class\->new()\->foo(); \& # Calls MyClass::Logging::foo, MyClass::UpperCase::foo, MyClass::foo .Ve .SH "DESCRIPTION" .IX Header "DESCRIPTION" This distribution facilitates the run-time generation of classes which inherit from a base class and some optional selection of mixin classes. .PP A factory is provided to generate the mixed classes with multiple inheritance. A \s-1NEXT\s0 method allows method redispatch up the inheritance chain. .SH "USAGE" .IX Header "USAGE" The Class::MixinFactory package is just a facade that loads the necessary classes and provides a few import options for compile-time convenience. .SS "Factory Interface" .IX Subsection "Factory Interface" To generate an object with some combination of mixins, you first pass the names of the mixin classes to a class factory which will generate a mixed class. (Or return the name of the already generated class, if there has been a previous request with the same combination of mixins.) .PP You can add a factory method to your base class, create a separate factory object, or inherit to produce a factory class. .IP "Factory Method" 4 .IX Item "Factory Method" To add a factory method to a base class, inherit from the Class::MixinFactory::HasAFactory class, or use the \f(CW\*(C`\-hasafactory\*(C'\fR import option: .Sp .Vb 2 \& package MyClass; \& use Class::MixinFactory \-hasafactory; \& \& package main; \& my $class = MyClass\->class( \*(AqLogging\*(Aq, \*(AqUpperCase\*(Aq ); \& print $class\->new()\->foo(); .Ve .IP "Factory Class" 4 .IX Item "Factory Class" To create a new class which will act as a factory for another base class, inherit from the Class::MixinFactory::Factory class, or use the \f(CW\*(C`\-isafactory\*(C'\fR import option: .Sp .Vb 3 \& package MyClass::Factory; \& use Class::MixinFactory \-isafactory; \& MyClass::Factory\->base_class( "MyClass" ); \& \& package main; \& my $class = MyClass::Factory\->class( \*(AqLogging\*(Aq, \*(AqUpperCase\*(Aq ); \& print $class\->new()\->foo(); .Ve .IP "Factory Object" 4 .IX Item "Factory Object" To create an object which will act as a factory, create a Class::MixinFactory::Factory instance by calling the \fInew()\fR method: .Sp .Vb 3 \& use Class::MixinFactory; \& my $factory = Class::MixinFactory\->new(); \& $factory\->base_class( "MyClass" ); \& \& my $class = $factory\->class( \*(AqLogging\*(Aq, \*(AqUpperCase\*(Aq ); \& print $class\->new()\->foo(); .Ve .SS "Inheriting from a Mixed Class" .IX Subsection "Inheriting from a Mixed Class" .IP "Inheriting with a Factory Method or Factory Object" 4 .IX Item "Inheriting with a Factory Method or Factory Object" A subclass can inherit from a mixed class: .Sp .Vb 3 \& package MyClass::CustomWidget; \& @ISA = MyClass\->class( \*(AqLogging\*(Aq, \*(AqUpperCase\*(Aq ); \& sub foo { local $_ = (shift)\->NEXT(\*(Aqfoo\*(Aq, @_); tr[a\-z][z\-a]; $_ } \& \& package main; \& print MyClass::CustomWidget\->new()\->foo(); .Ve .IP "Inheriting with a Factory Class" 4 .IX Item "Inheriting with a Factory Class" A subclass can use a factory class to define its own inheritance: .Sp .Vb 4 \& package MyClass::CustomWidget; \& use Class::MixinFactory \-isasubclass, \& MyClass::Factory => \*(AqLogging\*(Aq, \*(AqUpperCase\*(Aq; \& sub foo { local $_ = (shift)\->NEXT(\*(Aqfoo\*(Aq, @_); tr[a\-z][z\-a]; $_ } \& \& package main; \& print MyClass::CustomWidget\->new()\->foo(); .Ve .SS "Configuring a Factory" .IX Subsection "Configuring a Factory" Factories support methods that control which classes they will use. .PP The base class will be inherited from by all mixed classes. .PP .Vb 1 \& $factory\->base_class( "HelloWorld" ); .Ve .PP The mixin prefix is prepended to the mixin names passed to the \fIclass()\fR method. Mixin names that contain a \*(L"::\*(R" are assumed to be fully qualified and are not changed. If empty, the base_class is used. .PP .Vb 1 \& $factory\->mixin_prefix( \*(AqHelloFeature\*(Aq ); .Ve .PP The mixed prefix is at the start of all generated class names. If empty, the base_class is used, or the factory's class name. .PP .Vb 1 \& $factory\->mixed_prefix( \*(AqHelloClass\*(Aq ); .Ve .SS "Writing a Mixin Class" .IX Subsection "Writing a Mixin Class" Writing a mixin class is almost the same as writing a subclass, except where methods need to redispatch to the base-class implementation. (The SUPER::method syntax will only search for classes that the mixin itself inherits from; to search back up the inheritance tree and explore other branches, another redispatch mechanism is needed.) .PP A method named \s-1NEXT\s0 is provided to continue the search through to the next class which provides a given method. The order in which mixins are stacked is significant, so the caller should understand how their behaviors interact. (See Class::MixinFactory::NEXT.) .SH "SEE ALSO" .IX Header "SEE ALSO" For distribution, installation, support, copyright and license information, see Class::MixinFactory::ReadMe.