Object types

Objects are part of OCaml's full-fledged support for object-oriented programming (OOP). They combine some of the best properties of records and tuples: they are structural so we can create them in an adhoc way (without having to define their types), and we can provide field names (in OOP terminology, methods) that act as descriptive names. Here's an example:

/* src/Ch04/Ch04_Objects.re */
let bob = {as _; pub id = 1; pub name = "Bob"}; /* (1), (2) */

let greet(person) =
  "Hello, " ++
  person#name ++
  " with ID " ++
  string_of_int(person#id); /* (3) */

let jim = {
  pub id = 2;
  pub name = "Jim";
  pub sayHi = "Hi, my name is " ++ this#name /* (4) */
};

Js.log(greet(jim)); /* (5) */
/*Js.log(greet({as _; pub name = "Tom"}));*/

These show some basic usage of Reason objects:

1. Objects are delimited by brackets...