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Example of OO in Perl

Although Perl 5 doesn't use the words "class", "method" or "object" (or any of the other common OO words), it never the less has a very good OO model indeed - here's the source code of an example, together with the result of running the sample. I'll then give you a few clues!

use train;
use bus;
 
push (@ptl, new train("07:17",2,75));
push (@ptl, new train("06:40",3,60));
push (@ptl, new bus("07:12",2,40));
push (@ptl, new bus("08:10",1,61));
 
for $tranbit (@ptl) {
 print $tranbit;
 print " ",$tranbit->getstaff();
 print " ",$tranbit->getcapacity();
 print " ",$tranbit->getwhat();
 print "\n";
 }
 
__END__
 
The stuff below is comments as held in this
file. Split it out to separate files if you
want to run it!
 
############### train.pm
 
package train;
 
use pt;
@ISA = ("pt");
 
sub getstaff {
 return 1;
 }
 
sub getwhat {
 return ("Metal wheeler");
 }
 
1;
 
############### bus.pm
 
package bus;
 
use pt;
@ISA = ("pt");
 
sub getstaff {
 my ($self) = @_;
 return $$self{nv};
 }
 
sub getwhat {
 return ("Rubber wheeler");
 }
 
1;
 
####################### pt.pm
 
 
package pt;
 
sub new {
 my($class,$time,$nv,$vc)=@_;
 my %info;
 $info{time} = $time;
 $info{nv} = $nv;
 $info{vc} = $vc;
 bless \%info,$class;
 }
 
sub getcapacity {
 my ($self) = @_;
 return $$self{nv}*$$self{vc};
 }
 
1;
 
################## Runs as ...
 
 
j8pl grahamellis$ perl tharness
train=HASH(0x801c70) 1 150 Metal wheeler
train=HASH(0x815f60) 1 180 Metal wheeler
bus=HASH(0x815f9c) 2 80 Rubber wheeler
bus=HASH(0x815ff0) 1 61 Rubber wheeler
j8pl grahamellis$



Right. Now ...

A Perl package is a class
A Perl sub is used to define a method
The list @ISA defines inheritance
Perl's bless function defines the container for variables in the object
my defines a locally scoped variable
-> is used to invoke a method on an object
(written 2008-06-03)

 
Associated topics are indexed as below, or enter http://melksh.am/nnnn for individual articles
P213 - Perl - Creating your own Classes
  [4607] Classes and object - first steps in Perl 6 - (2016-01-02)
  [3833] Learning to use existing classes in Perl - (2012-08-10)
  [3098] Learning Object Orientation in Perl through bananas and perhaps Moose - (2010-12-21)
  [3059] Object Orientation in an hour and other Perl Lectures - (2010-11-18)
  [2969] What does blessing a variable in Perl mean? - (2010-09-24)
  [2877] Further more advanced Perl examples - (2010-07-19)
  [2834] Teaching examples in Perl - third and final part - (2010-06-27)
  [2169] When should I use OO techniques? - (2009-05-11)
  [1925] Introduction to Object Oriented Programming - (2008-12-06)
  [1864] Object Oriented Perl - First Steps - (2008-11-01)
  [1435] Object Oriented Programming in Perl - Course - (2007-11-18)
  [1320] Perl for Larger Projects - Object Oriented Perl - (2007-08-25)
  [983] Blessing in Perl / Member variable in Ruby - (2006-12-14)
  [975] Answering ALL the delegate's Perl questions - (2006-12-09)
  [246] When to bless a Perl variable - (2005-03-15)
  [227] Bellringing and Programming and Objects and Perl - (2005-02-25)

P218 - Perl - More Objects
  [4366] Changing what operators do on objects - a comparison across different programming languages - (2014-12-26)
  [4356] Object factories in C++, Python, PHP and Perl - (2014-12-19)
  [4098] Using object orientation for non-physical objects - (2013-05-22)
  [4096] Perl design patterns example - (2013-05-20)
  [3941] Building an object based on another object in Perl - (2012-12-03)
  [3581] Perl - calls to methods that use => - what do they mean? - (2012-01-16)
  [3377] What do I mean when I add things in Perl? - (2011-08-02)
  [3097] Making Perl class definitions more conventional and shorter - (2010-12-20)
  [2972] Some more advanced Perl examples from a recent course - (2010-09-27)
  [2876] Different perl examples - some corners I rarely explore - (2010-07-18)
  [2811] Igloos melt in the summer, but houses do not - (2010-06-15)
  [2717] The Multiple Inheritance Conundrum, interfaces and mixins - (2010-04-11)
  [2651] Calculation within objects - early, last minute, or cached? - (2010-02-26)
  [2427] Operator overloading - redefining addition and other Perl tricks - (2009-09-27)
  [1949] Nuclear Physics comes to our web site - (2008-12-17)
  [1819] Calling base class constructors - (2008-10-03)
  [1665] Factory method example - Perl - (2008-06-04)
  [1217] What are factory and singleton classes? - (2007-06-04)
  [930] -> , >= and => in Perl - (2006-11-18)
  [831] Comparison of Object Oriented Philosophy - Python, Java, C++, Perl - (2006-08-13)
  [656] Think about your design even if you don't use full UML - (2006-03-24)
  [592] NOT Gone phishing - (2006-02-05)
  [588] Changing @INC - where Perl loads its modules - (2006-02-02)
  [531] Packages in packages in Perl - (2005-12-16)


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Example of OO in Perl
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