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)

Higher-order functions and lambdas

The [+] reduction operator that we have just seen in the previous section is performing the action of the + operator as many times as needed to add up all the elements of the provided data.

In Perl 6, there is an alternative way of doing reduction operations. There exists a built-in function reduce that expects a code block that will execute the action. First, we will use the function add($a, $b) that we created in Chapter 2, Writing Code:

sub add($a, $b) {
return $a + $b;
}

say reduce &add, 10..15;

The reduce function takes the reference to a function as the first argument and a flattened list of values. In &add, the ampersand before the name of the function tells Perl 6 that this is not a function call but a code reference to a function.

The reduce function is an example of the higher-order function. One of its arguments is another...