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)

Using the actions class

The more complex a grammar becomes, the more complex the actions. Almost every rule or token in our current grammar has an action. Even if most of the actions are just one or two lines of code, the fact that the Perl 6 code is mixed with the grammar language makes reading the code difficult. Formatting the code also becomes a difficult task, as you need to add more spaces to indent the code properly. In this section, we will see what Perl 6 offers to tackle this issue.

All actions may be moved to a separate class. Thus, the complete grammar contains a grammar itself and an actions class. Correspondence between the grammar rules and tokens and the actions is achieved by simply giving the same names to the methods of the action class. Let us convert our grammar to use the split approach.

First of all, create a class for actions and pass it to the parser:

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