---

name: lea

prettier-ignore

description: Use when writing or modifying Lea code - pipe-oriented functional language with tree-walk interpreter

Lea Language

Quick Start

Copylet numbers = [1, 2, 3, 4, 5]

let result = numbers
  /> filter((x) -> x > 2)
  /> map((x) -> x * x)
  /> reduce(0, (acc, x) -> acc + x)

result /> print

Core Principles

• Pipes: value /> fn passes value as first arg; use input placeholder to control position
• Functions: let double = (x) -> x * 2 (no fn keyword)
• Multi-statement bodies: Indentation-based or brace-delimited { }
• Decorators: Trailing #log #memo #time #retry(3) etc. after function body
• Bindings: let x = 10 immutable, maybe x = 0 mutable
• Records: { name: "Max", age: 99 } with member access record.field
• Contexts: context Name = default + provide Name value + @Name attachments

Builtins

• Math: sqrt, abs, floor, ceil, round, min, max
• Lists: length, head, tail, push, concat, map, filter, reduce, range
• IO: print (returns first arg for chaining)
• Async: delay(ms) — promise that resolves after ms

Running

Copynpm run repl            # Interactive REPL
npm run lea file.lea    # Run a file

Reference Files

• references/syntax.md - Full syntax reference
• references/architecture.md - Interpreter internals