aoughwl

aoughwl is a rewrite of the Nim / Nimony compiler as a set of separate programs: a parser, a type checker, a lowering pass, and several code generators. Each one reads a file and writes a file, so you can stop after any stage and look at what it produced.

The intermediate format is AIF, which is byte-for-byte Nimony's NIF. That means our stages and Nimony's can be mixed: nifler, nimsem and hexer read and write the same files as aowlparser, aowlsem and aowlhexer. We wrote each stage from scratch and check it against the original by diffing the output bytes.

▶ Open the Playground

The playground runs the parser, checker and interpreter in your browser, with nothing to install.

Status

• Parser: byte-exact against nifler on the whole compiler tree, with no crashes or hangs across four corpora.
• Type checker: 924 of 941 corpus cases byte-exact, and std/system type-checks to within 89 tokens (measured 2026-09-09, on Windows).
• Lowering: still runs Nimony's own passes. The page says so.

Everything that is missing, and why, is on the parity page.

Stages

 .nim ─► aowlparser ─► aowlsem ─► aowlhexer ─┬─ aowlc   C / native
         parse         typecheck  lower       ├─ aowljs  JavaScript
                                              ├─ aowlweb JavaScript + WASM
                                              ├─ aowli   interpreter
                                              └─ aowlts, aowlpy  TypeScript, Python

Stage	What it does
aowlparser	Nim source → .p.nif. Self-hosted, and runs in a browser.
aowlsem	.p.nif → typed .s.nif: symbols, overloads, generic instantiation.
aowlhexer	.s.nif → .c.nif: ARC, closures, iterators, exceptions, monomorphisation. Private.
aowlmony	The driver. One command from .nim to a native binary, an interpreted run, or a web build.
aowlrt	The runtime (strings, seqs, ARC) that the C and JS backends link against.
aowlhl	A shared high-level IR that feeds the TypeScript and Python emitters.

Backends

Backend	Output
aowlc	C, linked with gcc.
aowljs	JavaScript, close to native speed.
aowlweb	JavaScript and WebAssembly over one linear-memory model, with an async runtime.
aowli	A tree-walking interpreter and a bytecode VM, plus a stepping debugger.
aowlts	TypeScript.
aowlpy	Python.

JavaScript engine

Project	What it does
aowljs-engine	Runs JavaScript: an interpreter and an x86-64 JIT written in nimony. Passes 53,477 of 53,479 test262 tests; faster than QuickJS and V8's interpreter on its benchmarks.

Tools

Tool	What it does
aowlup	Installs and selects the components.
aowlcode	Claude Code plugin and MCP server for working on the toolchain.
aowllsp	Language server and VS Code extension.
aowlsuggest	Diagnostics and quick-fixes.
aowlfmt	Formatter. It re-parses its output and leaves your file alone if anything but whitespace changed.
aowltest	Test runner. It skips tests whose inputs are unchanged and reports the cache hit rate.
aowlhost	Runs a module as a plugin with no capabilities unless you grant them.
aowllens	Reads .s.nif and prints JSON: declarations, outline, type at a position.

Libraries: net stack (TCP, TLS 1.3, HTTP, WebSocket), LLM clients, web / html / css, regex, unicode, jit, ovh.

Source and price

Paid: aowli, its debugger, and the TypeScript, Python and JavaScript/WASM backends are one $9.99/month subscription, installed with aowlup login YOUR-KEY. See the store page. A second product, Jester, is upcoming at $19.99/month.

Public repos: aowlparser, aowlmony, aowlup, aowlrt, aowlhl, aowlfmt, aowllsp, aowlsuggest, aiflens, aowljs, aowljs-engine, aowlc.

Private repos: aowlsem, aowlhexer, aowlhost, aowlcode, aowltest, and the four paid components (aowli, aowlweb, aowlts, aowlpy). The docs for all of them are public.

Contact

Ask on Discord (timbuktu_guy). Questions about how something works are welcome, and so is disputing the parity numbers.