Roc — Fast Friendly Functional Programming Language

Introduction

Roc is a statically typed functional programming language created by Richard Feldman (creator of Elm's architecture). It prioritizes fast compilation, fast execution, and a friendly developer experience with helpful error messages and minimal boilerplate.

What Roc Does

• Compiles to native machine code for fast execution
• Provides exhaustive pattern matching and algebraic data types
• Offers a platform system for separating pure logic from side effects
• Delivers fast incremental compilation for rapid feedback
• Produces helpful error messages with suggested fixes

Architecture Overview

Roc uses a unique platform/application split. Applications contain pure business logic while platforms handle I/O and side effects. The compiler is written in Rust and Zig, producing LLVM IR that compiles to native binaries. This architecture enables guaranteed purity in application code while maintaining practical I/O capabilities through the platform layer.

Self-Hosting & Configuration

• Install via the official installer or build from source
• Create a new project with roc init
• Choose a platform (basic-cli, basic-webserver) in your app header
• No build configuration files needed; the app header declares dependencies
• Supports cross-compilation for different target architectures

Key Features

• No runtime exceptions with exhaustive pattern matching
• Platform system cleanly separates pure and effectful code
• Fast incremental compilation with sub-second rebuilds
• Automatic memory management without garbage collection pauses
• Friendly error messages designed for newcomers

Comparison with Similar Tools

• Elm — Browser-only functional language; Roc targets general-purpose native applications
• Haskell — Academic FP language; Roc prioritizes approachability and compilation speed
• Rust — Systems language with ownership; Roc uses automatic memory management
• OCaml — Mature ML family language; Roc offers simpler syntax and better error messages

FAQ

Q: Is Roc ready for production? A: Roc is pre-1.0 and under active development. It is usable for personal projects and experimentation.

Q: What platforms are available? A: basic-cli for command-line tools, basic-webserver for HTTP servers, and community platforms for other use cases.

Q: Does Roc have a package manager? A: Roc uses URL-based dependencies declared in the app header. A centralized registry is planned.

Q: How does memory management work? A: Roc uses automatic reference counting with compile-time optimizations to eliminate most overhead.

Sources

• https://github.com/roc-lang/roc
• https://www.roc-lang.org