With more than examples, Perl Black Book, 2nd Edition is a complete reference to the Perl language ranging from language syntax and idioms to its use in. Perl Black Book: The Most Comprehensive Perl Reference Available Today Paperback – August 14, Steven Holzner (Cambridge, MA) is a former contributing editor for PC Magazine and has authored more than 60 books ranging in subject from assembly language to C++. Perl Black Book book. Read reviews from world's largest community for readers. Written by Steve Holzner, former contributing editor for PC Magazine and t.
|Language:||English, Spanish, German|
|Genre:||Politics & Laws|
|Distribution:||Free* [*Registration needed]|
An Introduction Draft - Richard S. Sutton, Andrew G. Beezer Advanced Algebra - Anthony W. Grinstead and J. Downey Think Stats: Probability and Statistics for Programmers - Allen B. A Quickstart guide - Paul Swartout, Packt.
Edward Lavieri, Packt. Pretty Darn Quick: Selected Essays of Richard M. Gabriel Open Advice: Downey Think OS: Demeyer, S. Ducasse and O. A piece of cake! Smith ASP. Shotts, Jr. A Programmer's Guide - Jonathan E. David Carlson and Br. Morelli and R.
Souza and Fabio M. Adams, Packt. The Definitive Guide - Matthew A.
Cooper, Jr. An Interactive Approach - Stuart C. Hoyte Lisp Hackers: This book contains Training materials for new and…. Many web applications are implemented in a way that makes developing them difficult and repetitive. Catalyst is an open source Perl-based Model-View-Controller framework that aims to solve this problem by reorganizing your web application to design and implement it in a natural, maintainable, and testable manner, making web….
Over the years, Perl has grown from an elegant scripting tool into a mature and full-featured language for application development, boasting object-oriented programming, a flexible threading model, built-in support for Unicode, and a thriving community. Available on almost every platform, and offering a comprehensive library of modules, there…. Combining the best features of C, UNIX utilities, and regular expressions, Perl has grown as one of the most powerful and popular scripting languages.
You should be able to call the new operator with the class name as the first parameter. This capability to parse the class name from the first argument causes the class to be inherited. The following code uses the function call ref to determine if the class exists per se. The ref function returns true if the item passed to it is a reference and null if it is not a reference.
With classes, the true value returned from the ref function is the name of the class. Outside the class package, the reference is generally treated as an opaque value that can only be accessed through the class's methods.
You can access the values within the package directly, but it's not a good idea to do so because such access defeats the whole purpose of object orientation. It's possible to bless a reference object more than once. However, the caveat is that the new class must get rid of the object at the previously blessed reference. For C and Pascal programmers, this is like assigning a pointer to malloced memory and then assigning the same pointer to another location without first freeing the previous location.
In effect, a Perl object must belong to only one class at a time. What's the real difference between an object and a reference? Perl objects are blessed to belong to a class. References are not blessed; if they are, they belong to a class and are objects. Objects know to which class they belong. References do not have a class to which they belong. Instance Variables The arguments to a new function for a constructor are called instance variables.
Instance variables are used to do initialization for each instance of an object as it's created. For example, the new function could expect a name for each new instance of the object created. Using instance variables allows you to customize each object as it is created. You can use either an anonymous array or anonymous hash to hold instance variables.
Perl doesn't provide any special syntax for method definition. A method expects its first argument to be the object or package on which it is invoked. Perl has two types of methods: static and virtual.
A static method expects a class name as the first argument. A virtual method expects a reference to an object as the first argument. The way each method handles the first argument determines whether the method is static or virtual.
A static method applies functionality to the entire class as a whole because it uses the name of the class. Functionality in static methods is therefore applicable to all objects of the class. Generally, static methods ignore the first argument because they already know which class they are in.
Constructors are static methods. A virtual method expects a reference to an object as its first argument.
Typically, the first thing a virtual method does is shift the first argument into a self or this variable and then use that shifted value as an ordinary reference. For example, consider the following code: 1. TIP Look at the.
Exporting Methods If you tried to invoke the Cocoa. This error occurs because the Cocoa. To export these functions, you need the Exporter module. The ISA array does not have to be defined in every package; however, when it is defined, Perl treats it as a special array of directory names.
This array is similar to the INC array, where directories are searched for files to include. The ISA array contains the names of the classes packages to look for methods in other classes in if a method in the current package is not found.
The ISA array contains the names of the base classes from which the current class inherits. The search is done in the order that the classes are listed in the ISA arrays. All methods called by a class must belong to the same class or the base classes defined in the ISA array.