Subrust, a no_std, no alloc Subset-of-Rust interpreter

Name: Subrust, a no_std, no alloc Subset-of-Rust interpreter
Availability: InStock
Author: makira

by makira·Jul 19, 2026·2 points·0 comments

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AI Analysis

●●●BangerWizardryBig BrainNiche Gem

Guarantees interpreted scripts behave identically to rustc compilation with zero dependencies.

Strengths

•Differential testing enforces L1/L2 laws: accepted code must compile and match rustc output exactly.
•Bootstraps from a 229-byte seed and self-hosts, proving the minimal core is sufficient.
•Resumable machine architecture suspends on host calls, giving embedders total control over effects.

Weaknesses

•Supports only a strict subset of Rust, limiting utility for complex user-written logic.
•Relies on LLMs to generate scripts since the subset syntax may be unfamiliar to humans.

Post Description

I needed to run user scripts for an app, and decided to use a subset of Rust as the scripting language. I do not expect a typical user to write the script directly, a local LLM will handle it. The interpreter can be bootstrapped in a C-free path from a tiny 229 bytes seed, and self-hosts. The code was written by Claude Code (Fable/Opus) under my supervision, in a few days, which I found impressive.