The O'Caml Reactive Toolkit (ORT for short) is a library for creating GUIs in a functional style. This means that instead of actively manipulating widget properties and writing callbacks as with traditional GUI toolkits, ORT allows the programmer to write functions describing the relationship between widgets and their contents. This has the same benefits over traditional toolkits as functional programming does over imperative programming; namely, it allows simpler, cleaner, and more bug-free code to be created.
This tutorial is designed for O'Caml programmers who may or may not have any GUI programming experience, and who have little or no experience with the functional reactive programming style. Before starting the tutorial it is highly recommended that you download and install ORT so that you may experiment with the examples as you go along. Installation instructions can be found in the reference manual.
On to the first example!