Read Lisp
Parse Emacs Lisp forms, 1+5+2 extension packs, persistent literals, modules, macros, and explicit host boundaries.
175stable specifications
598checked library exports
35/35core criteria retained passing
0tracked .mjs source files
One language, two compiler generations, four execution targets.
Plain Emacs runs the 100% compatible core and builds the seed. The seed builds the self-hosted Eliscript compiler across stage0–stage3, emitting readable, source-mapped ESM alongside zero-glue WASM and ARM64 native binaries.
Prove semantics
Expand deterministically, check static contracts and pre/post assertions, validate transient ownership, and verify tail recursion.
Lower explicit IR
Seed and self-hosted stage1–stage3 compilers produce identical versioned IR, diagnostics, and Source Map v3 locations.
Run across targets
Execute identically in Emacs Lisp, standard ESM (Bun, Node, browser), and zero-glue WASM / ARM64 native `:abi` targets.
Small forms, strong guarantees.
Switch between language mechanisms. The right pane describes the behavior the compiler and runtime preserve across Emacs and JS hosts.
Eliscript
(defun sum-to (n total)
(if (= n 0)
total
(recur (1- n) (+ total n))))
Runtime contract
tail position verified
arguments evaluated once, left to right
function frame reused as a loop
constant JavaScript stack100% Emacs Lisp core + 1+5+2 explicit extensions.
Standard Emacs Lisp works unchanged by default, while seven modular extension packs add static contracts, persistent data, unified destructuring, lexical modules, structured async, explicit JS sentinels, and multi-backend native ABI lowering.
Lisp-2 & static declarations
100% Emacs Lisp default semantics (Lisp-2, nil-only falsiness, integer division, condition-case, pcase) plus opt-in declare type, purity, and pre/post contracts.
Share structure, not mutation
7 persistent collections (List, Vector, HAMT Map/Set, Queue, AVL Sorted Map/Set), cl-defstruct-persistent with JSON Schema round-trip, state-cell, Transducers, and Transients.
Unified pcase superset
defun-case multi-arity dispatch, let-bind / defun-bind / pcase-value destructuring, let-const, 50,000-depth recur, thread-some->, and fn-* combinators.
Lexical privacy & pure macros
defmodule with lexical-private bindings, explicit :export / :import, and defvar-once hot-reload state, plus sandboxed defmacro-checked.
Structured concurrency & sentinels
defun-async / await, with-async-scope cancellation, backpressure async-channel, handle revocation, and lossless js-false / js-null / js-undefined sentinels.
Emacs · JS · WASM · Native
Explicit :abi (:numeric-f64 / :memory-u32) declarations and linear-memory operators execute with identical results across Emacs, ESM, WASM, and ARM64 native binaries.
The maturity baseline is real. The language keeps moving.
All 42 implementation units, 35 mandatory verification criteria, and 173 stabilization units are complete in the retained core evidence. Future work is tracked without retroactively inflating that result; general automatic tail-call optimization begins as a Draft and Pending specification.