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)

On-demand supplies

The data flow of supplies contains two parts—the supplier that emits data and the tap that receives it. Perl 6's reactive programming model is a thread-safe implementation of the Observer design pattern.

Let us create our first on-demand supply using the supply keyword:

supply {
emit($_) for 'a'..'e';
}

The supply is here but it does not emit any data yet because there is no demand. You can easily see this if you add a print instruction to the loop:

supply {
for 'a'..'e' {
emit($_);
say "Emitted $_";
}
}
sleep 2;

The program just silently quits after 2 seconds.

To make the supply generate data, we need to create a tap. The supply block returns a value of the Supply type, and you can call the tap method on it to pass the code that will be executed in response to the data emitted...