wart

Experimental WebAssembly runtime and CLI written in Zig.

Status

This repository contains an interpreter, CLI, benchmark harness, and partial implementations for WASI Preview 1, Preview 2, Preview 3, and WASIX-related modules. It does not currently claim full conformance with the WebAssembly proposals, WASI component model, or WASIX, and benchmark results must be measured locally instead of inferred from checked-in reports.

Build

zig build
zig build run -- examples/simple.wasm
zig build test

Nix builds are also expected to work:

nix build
nix build .#debug
nix build .#small

Benchmarking

Use the repository benchmark entry points to compare wart against any runtimes installed on your machine:

zig build bench
bash bench.sh
wart bench
wart bench run --profile core-universal --format markdown --output bench/results

bench.sh builds wart, detects available runtimes, runs shared workloads, and records machine-generated results under bench/results/ when hyperfine is installed. The benchmark scripts do not assume wart wins; they report measured timings.

Verification

Pinned suite and benchmark metadata now live in the repository so claims can be tied to explicit artifacts instead of checked-in summaries:

bash scripts/fetch-spec-suites.sh
wart verify spec --profile all --format markdown --output artifacts/spec
wart inspect capabilities --format json

wart verify spec currently reports unsupported upstream runner integrations explicitly rather than pretending the runtime is already conformant.

Repository Layout

• src/ contains the CLI, runtime, and WASI-related modules.
• test/ contains smoke tests and runtime unit tests.
• examples/ contains small fixtures and sample workloads.
• bench/ contains benchmark inputs and harnesses.

Scope

The long-term goal is broader WebAssembly, WASI, and WASIX coverage, but that work is still incomplete. Treat this repository as an in-progress runtime rather than a finished conformance target.