Idris 2: Quantitative Type Theory in Practice (Artifact)

Abstract

Dependent types allow us to express precisely what a function is intended to do. Recent work on Quantitative Type Theory (QTT) extends dependent type systems with linearity, also allowing precision in expressing when a function can run. This is promising, because it suggests the ability to design and reason about resource usage protocols, such as we might find in distributed and concurrent programming, where the state of a communication channel changes throughout program execution.
Idris 2 is a new version of Idris, implemented in itself, and based on Quantitative Type Theory. The paper introduces Idris 2 and describes how QTT has influenced its design, as well as giving several examples of how to use QTT in practice. The artifact, correspondingly, provides an implementation of Idris 2, running on a virtual machine, along with runnable examples from the paper. This document explains how to install the artifact, how to run the examples, and suggests some small ways to experiment with and modify the examples.