Free Variable as Effect, in Practice

TL;DR

This paper explores the practical benefits of algebraic effects for handling free variables, proposing a new approach that simplifies compiler design and enhances type-checking and variable analysis.

Contribution

It introduces a novel practical application of algebraic effects to improve compiler construction and variable management, moving beyond theoretical considerations.

Findings

Prototype demonstrates improved incremental type-checking

Simplifies variable usage and leaf function analyses

Potential for more efficient compiler implementations

Abstract

Variable environment is the time-honored way of making sense of free variables, used in programming language theory as well when writing interpreters and some compilers. Algebraic effects give another way, as was pointed already at HOPE 2017. Although a theoretical curiosity, it may have surprising practical benefits: a new way of writing compilers, with the incremental type-checking, with easy variable usage, leaf function analyses. This work-in-progress report prototypes and illustrates the idea.