# Lea > Use when writing or modifying Lea code - pipe-oriented functional language with tree-walk interpreter - Skill: `tomevault-io/lea` (Agent Skill, multi-file: 2 files) - Install (CLI): `npx skillmds@latest add tomevault-io/lea` - Raw SKILL.md: https://api.skillmd.com/api/skills/tomevault-io/lea/raw - Safety review: pending (external: skill-scanner PASS, skillspector PASS) - Works with: Claude Code, Claude.ai, OpenAI Codex - Category: Coding & Dev Tools - Author: tomevault-io (https://skillmd.com/u/tomevault-io) - Updated: 2026-09-17 - Page: https://skillmd.com/skills/tomevault-io/lea --- # Lea Language ## Quick Start ```lea let 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 ```bash npm run repl # Interactive REPL npm run lea file.lea # Run a file ``` ## Reference Files - [references/syntax.md](references/syntax.md) - Full syntax reference - [references/architecture.md](references/architecture.md) - Interpreter internals --- > Converted and distributed by [TomeVault](https://tomevault.io/claim/mcclowes) — claim your Tome and manage your conversions.