Book Image

Learn Red ? Fundamentals of Red

By : Ivo Balbaert
Book Image

Learn Red ? Fundamentals of Red

By: Ivo Balbaert

Overview of this book

A key problem of software development today is software bloat, where huge toolchains and development environments are needed in software coding and deployment. Red significantly reduces this bloat by offering a minimalist but complete toolchain. This is the first introductory book about it, and it will get you up and running with Red as quickly as possible. This book shows you how to write effective functions, reduce code redundancies, and improve code reuse. It will be helpful for new programmers who are starting out with Red to explore its wide and ever-growing package ecosystem and also for experienced developers who want to add Red to their skill set. The book presents the fundamentals of programming in Red and in-depth informative examples using a step-by-step approach. You will be taken through concepts and examples such as doing simple metaprogramming, functions, collections, GUI applications, and more. By the end of the book, you will be fully equipped to start your own projects in Red.
Table of Contents (13 chapters)
11
Assessments

Working with functions

In this section, we will talk about how to make functions resistant to possible errors.

Error handling

In the previous section, we saw that passing the wrong type of argument to a function causes the program to terminate with an error message. Is there a way to guard functions against wrong types and still let the program continue? We know how to test types with type?, so we can do that instead. Here is a version of the inc function that is untyped, but protected against the possibility of n not being an integer:

inc: func [n][
if not integer? n [
print ["n must be an integer, not a" (type? n)]
exit
]
n + 1
]

inc 9 ;== 10
inc pi ;== n must be an integer, not a...