Book Image

Perl 6 Deep Dive

By : Andrew Shitov
Book Image

Perl 6 Deep Dive

By: Andrew Shitov

Overview of this book

Perl is a family of high-level, general-purpose, interpreted, dynamic programming languages consisting of Perl 5 and Perl 6. Perl 6 helps developers write concise and declarative code that is easy to maintain. This book is an end-to-end guide that will help non-Perl developers get to grips with the language and use it to solve real-world problems. Beginning with a brief introduction to Perl 6, the first module in the book will teach you how to write and execute basic programs. The second module delves into language constructs, where you will learn about the built-in data types, variables, operators, modules, subroutines, and so on available in Perl 6. Here the book also delves deeply into data manipulation (for example, strings and text files) and you will learn how to create safe and correct Perl 6 modules. You will learn to create software in Perl by following the Object Oriented Paradigm. The final module explains in detail the incredible concurrency support provided by Perl 6. Here you will also learn about regexes, functional programming, and reactive programming in Perl 6. By the end of the book, with the help of a number of examples that you can follow and immediately run, modify, and use in practice, you will be fully conversant with the benefits of Perl 6.
Table of Contents (15 chapters)

Extracting substrings with capturing

Matching against regexes is not enough. The real power of regular expressions is not complete without the ability to extract the substrings that agreed with the regex pattern. Saving the parts of the string in special variables is called capturing.

Capturing groups

In Perl 6, capturing is achieved by placing the part of a regex in parentheses. Parentheses have as dual meaning in regexes. We already have seen the usage of parentheses for grouping alternatives in the phone number.

Let us continue with the example of extracting values of HTML attributes. We want now to print the values. So, we need to create a regex and mark the borders of the data that we want to extract. Captured data is...