Stageleft: Multi-stage Programming in Standard Rust

Rust has emerged as a popular systems language with growing interest in metaprogramming, yet it lacks staging support—developers must write unsafe, untyped macros instead. We present Stageleft, a library that brings type-safe staged programming to standard Rust without compiler modifications. Stageleft ensures hygienic code generation through ahead-of-time AST analysis, and handles free variables via a trait system that respects Rust's ownership rules. Stageleft demonstrates that staging can be practical and safe in Rust, enabling domain-specific optimizations while maintaining familiar developer interfaces.