Getting Started with Lispex

This is an earlier getting-started guide. To start learning with the current documentation, open First Program or Learning Path.

Welcome! The fastest way to learn Lispex is to run it directly. Use the Playground for a zero-install first look, install the npm CLI if you already work in Node, or install the standalone native binary when you want dependency-free scripts and Lispex Vouch receipt generation.

Install or run in the browser

Playground. The quickest way to run Lispex is the in-site Playground. A reference interpreter, written in Rust and compiled to WASM, executes your code entirely in the browser.

Native binary. Install the standalone binary when you want lispex diff-receipt, a dependency-free CLI, or a server/script install with no Node.

BASH

# macOS / Linux
curl -fsSL https://www.lispex.com/install.sh | sh

POWERSHELL

# Windows PowerShell
irm https://www.lispex.com/install.ps1 | iex

You can also download binaries and checksums manually from the Downloads page.

npm. Use npm when you already have Node 18+ and need lispex run, lispex verify, or lispex replay.

BASH

npm install -g lispex

The npm CLI and Playground use the WASM build of the same Rust reference interpreter. The native binary uses the same reference interpreter directly and is the public receipt generator.

Confirm the install:

BASH

lispex --version

Run your first program

Create hello.lspx. The first line is an optional header that pins the input grammar version.

LISPEX

;! lispex 1.4

(define message "Hello, Lispex!")
message

Run it.

BASH

lispex run hello.lspx

The browser Playground and the CLI use the same reference interpreter semantics. In v1.4 that shared path includes the refreshed multiple-value and higher-order call surface: apply, values, call-with-values, modulo, string-append, and number->string are exercised across the native interpreter and the WASM build used by the Playground and npm package.

Check Lispex Vouch artifacts

Lispex Vouch adds an evidence workflow for the rule corpora you commit in your own projects. lispex verify checks a differential receipt offline, and lispex replay compares a decision corpus against a version or a set of receipts.

BASH

lispex diff-receipt --input inputs/age-threshold.datum rules/age-threshold.lspx > receipts/age-threshold.json
lispex verify receipts/age-threshold.json
lispex replay decision-gallery --against decision-gallery/expected

Use the native standalone binary for the first command. It is the public receipt generator and writes csk.differential-receipt/v0 JSON to stdout. The npm CLI owns offline verify and replay for existing artifacts. The receipt records the exact rule, input, observations, and hashes. Native Vouch adds publisher authentication and current execution agreement, while the host application records who applied the resulting decision, when, and to which deployment.

Next steps

Run more code instantly in the Playground.
Download a standalone binary on the Downloads page.
Explore Syntax for tokens, literals, core and derived forms, and normalization rules.
Write your first real rules, a refund approval and a discount rate, in Writing Decision Rules.
Browse the guides on Capability Modules and Target Run Tips.
Read Lispex Vouch for the checked subset, receipts, verify, and replay.

We’re excited to see what you’ll build with Lispex.