Elle Programming Language

Welcome to Elle

Elle is a Lisp. What separates it from other Lisps is the depth of its static analysis: full binding resolution, capture analysis, and signal inference happen at compile time, before any code runs. This gives Elle a sound signal system, fully hygienic macros, colorless concurrency via fibers, and deterministic memory management — all derived from the same analysis pass.

What Makes Elle Different

• Fibers — independent execution contexts with their own stack, call frames, signal mask, and heap. Cooperative and explicitly resumed. When a fiber finishes, its heap is freed in O(1) — no GC pause, no reference counting.
• Signals — typed, cooperative flow-control interrupts. A signal is a keyword (:error, :log, :abort, or user-defined) that a fiber emits to its parent. The compiler infers which functions can emit signals.
• Hygienic Macros — full metaprogramming with defmacro, quasiquote/unquote, gensym, and scope sets
• Colorless Concurrency — fibers, coroutines, and OS threads from the same primitives
• Mutable/Immutable Split — [array] vs @[array], {struct} vs @{struct}, "str" vs @"str"
• Pattern Matching — match with destructuring, struct tags, wildcards, and & rest
• FFI — call C functions directly with ffi/native and ffi/defbind
• Bytecode Compilation — programs are compiled to bytecode with optional JIT
• Module System — closure-as-module with parametric imports

Quick Example

A fiber yields progress updates; the parent drives it to completion:

(defn process-items [items]
  (each item items
    (emit :progress {:item item :result (* item item)})))

(def f (fiber/new (fn [] (process-items [1 2 3])) |:progress|))

(forever
  (fiber/resume f)
  (if (= (fiber/status f) :paused)
    (print "progress:" (fiber/value f))
    (break)))

When the fiber finishes, its entire heap is freed in O(1).

Documentation

Elle ships with comprehensive design documents and runnable examples:

• Getting Started — installation and first steps
• Language Guide — data types, functions, and control flow
• Concurrency — fibers, coroutines, signals, and threads
• Documentation — language reference, design documents, and contributor guides
• Examples — 20+ runnable programs covering every major feature
• Standard Library — all built-in functions, auto-generated from runtime metadata