1 About this book

1.1 Questions and answers about this book

• What am I going to learn?
  • This book teaches the programming language ReasonML by Facebook.
  • It is also an introduction to functional programming. Especially people familiar with C-style languages (Java, JavaScript, C#, etc.) will profit from ReasonML’s familiar syntax.
• Is there any required knowledge?
  • You should know how to program, e.g. in a mainstream language such as Java, JavaScript, C#, Python, C/C++, PHP, Ruby, Go, etc.
• How can I get started a quickly as possible?
  • Read the whole book in order, skip chapters and sections marked as “advanced”.
• Does this book cover all of ReasonML?
  • This book explains the language and functional programming. It also gives tips for using the standard library.
  • It does not cover ReasonReact and JavaScript interop. Chapter “What to read next?” points to information on those topics.

1.2 Warning: This book is outdated

Sadly, after the initial version, I couldn’t afford to keep this book updated. It describes ReasonML as of 2018.

1.3 About the cover

Image by courtesy of the National Gallery of Art:

• “A Dromedary” (1551–1572) by Georg Mattheus. Woodcut on laid paper.
• URL: https://www.nga.gov/collection/art-object-page.153950.html