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)

Type constraints

In Perl 6, you don't have to declare a type of a variable, but you can do so if you want to. The same rules apply to the arguments of a sub and to its return value.

Typed parameters

In the previous sections of this chapter, we did not say anything about the types of the $a and $b parameters of the add function. The code of the sub assumes that the arguments should be numeric because the + operator is used. Calling a function with two strings as arguments, for example, add('Hello', 'World'), will generate the following runtime error:

Cannot convert string to number: base-10 number must begin with valid digits or '.' in 'Hello' (indicated by )

This exception happens...