Web Development with ReasonML

Creating Modules

Just as there’s not a lot to defining records, there’s not much to the basics of modules. In fact, we’ve been working with modules all along—any re file is automatically a module, as we saw when we put the shirt size data type and its associated functions in a separate file. You can also create a module within a file by using the keyword module, the module name (which must begin with a capital letter), an equal sign, and then code in braces. Anything you could put in a ReasonML file can be in a module definition.

So let’s expand our type definitions and add utility functions for converting to and from strings in our types, each of which will be in its own mini-module. First, let’s look at the Size module:

records/mod-shirts/src/Shirts.re ...