Perl Programming

Duration: 3 days
Type: beginner

Description

This course provides a complete introduction to the Perl scripting language. It includes both the latest features in Perl 5.10 and details of how the language is being redesigned in Perl 6. As the course progresses delegates learn to read data from files, filter it using regular expressions and store the result in data structures built from anonymous arrays and hashes. Best practises for Perl coding are introduced in each chapter, including techniques for creating reusable modules, classes and CPAN libraries.

Prerequisites

Delegates should have some previous programming experience, ideally in C, C++, C#, Java or JavaScript. By default the course is delivered on Windows using ActivePerl and the Komodo IDE, but other configurations are possible if required.

List of Modules

Introduction to Perl

The evolution of Perl from Sed, Awk and Shell Scripting
Installing Perl and downloading modules from CPAN
Understanding how the Perl interpreter runs your script
Differences between versions 5 and 6 of Perl
Comparing Perl to Python and Ruby

Key Characteristics of Perl

Sigils are used to denote variables
How barewords are interpreted
Packages, symbol tables and typeglobs
Strings, comments and using heredoc
Printing to and reading from the console

Basic Procedural Programming

Declaring and initializing scalar variables
Operators for strings and numbers
What values count as true in Perl
Variables created by the interpreter
Performing tests using if and unless
Different types of loops supported by Perl

File Access in Perl

Creating handles and testing file paths
Storing file handles in scalar variables
Reading lines, characters and binary data
Different techniques for slurping files
File globbing and changing permissions

Arrays and Lists

Initializing arrays based on lists
Initializing arrays implicitly
Initializing list values based on arrays
Slicing, expanding and shrinking arrays
Built-in functions for manipulating arrays
Introducing anonymous arrays

Working With Hashes

Initializing hashes based on lists
Initializing hashes implicitly
Using the 'fat comma' notation
Built-in functions for manipulating hashes
Initializing an array based on a hash
Using slices to add and retrieve multiple values
Creating hashes of anonymous arrays

The Perl Regular Expression Syntax

How a Regular Expression Engine operates
Creating character classes and specifying multiplicities
Shortcuts for character classes provided by Perl and POSIX
Meta-characters for specifying positions in the input
Using parenthesis for grouping and submatches

Running Regular Expressions in Perl

Using the =~ operator for pattern matching
Iterating over all the matches for an expression
Modifiers that can be used during matching
Using the extended regular expression syntax
Using the =~ operator for making substitutions
Using the e modifier to run code during substitutions

Regular Expressions - Advanced Concepts

The non greedy versions of *, + and ?
Using parenthesis that do not capture
Applying modifiers only to part of the expression
Using look-around assertions to match without capturing
Building regular expressions dynamically
Using Unicode properties in expressions
Named submatches in Perl 5.10

Subroutines in Perl

Declaring subroutines and passing parameters
Using hashes to implement named parameters
Creating local variables with my, our and local
Using anonymous subroutines for meta-programming

Perl Error Handling

Using eval to catch and handle errors
Enhanced error handling provided by Carp

References in Perl

Introducing references as memory addresses
Declaring references to named and anonymous variables
The different syntaxes available for working with arrays
Using references to create complex data structures
Best practises for navigating complex data structures

Creating Perl Modules

Understanding how packages work in Perl
The relationship between packages and modules
How the Exporter module exports symbols
Using the EXPORT, EXPORT_OK and EXPORT_FAIL arrays
Implementing versioning in your modules
Publishing modules to CPAN

Object Orientation in Perl

Reviewing the key concepts of OO
The effect of the bless keyword in Perl
Declaring classes with fields and methods
Creating class hierarchies and overriding methods

Using Perl Libraries (Optional)

Manipulating XML with SAX/DOM/XPath
Database access with DBI
Creating Web Applications

New Features in Perl 6 (Optional)

Sigils are now invariant
Better syntax for indexing
Modifications to operators
Changes to regular expressions
Changes to Object Orientation
Changes to references