ReasonML Quick Start Guide

Using module signatures

Let's imagine that we're building an invoice-management system and we have an Invoice module that defines an invoice type along with a function that other modules can use to create values of that type. This arrangement is shown in the following code:

/* Invoice.re */type t = {  name: string,  email: string,  date: Js.Date.t,  total: float};let make = (~name, ~email, ~date, ~total) => {  name,  email,  date,  total};

Let's also suppose that we have another module that is responsible for sending emails to customers, as shown in the following code:

/* Email.re */let send = invoice: Invoice.t => ...let invoice =  Invoice.make(    ~name="Raphael",    ~email="[e-mail]",    ~date=Js.Date.make(),    ~total=15.0,  );send(invoice); ...