Warning DEPRECATED As of April 2023 the Alexa Games team will no longer support or maintain this official distribution of Litexa. Thank you to all the folks who have used Litexa to make great Alexa skills over the years!

Litexa (archived!)

Litexa is an Alexa domain specific language, developed for long form multi-turn skills such as games. Its parser and tooling is implemented in Node.js and it compiles into JavaScript that expects Node.js as a runtime environment.

Full documentation is available at https://litexa.com

Disclaimer: Litexa we an Alexa Labs community-supported project (alpha) from the Alexa Games team at Amazon, where we used Litexa to develop and ship many Alexa skills. As of April 2023 we no longer support ongoing development of and with Litexa, and so this official repository is deprecated. Thank you to everyone who made great Alexa skills with this project!

Packages

The following packages are in this repo.

@litexa/core

The compiler and common tooling for Litexa. Installing this globally installs the Litexa command line tool.

@litexa/deploy-aws

A deployment module that pushes a skill to AWS using the services: Lambda, DynamoDB, and S3. Click to learn more about the Litexa deployment module.

@litexa/apl

An extension that makes working with APL documents in your Litexa project more powerful with shorthand for managing APL documents and common design patterns. Click to learn more about the APL extension.

@litexa/html

An extension that makes working with HTML web apps as part of the Alexa WebAPI for Games a little easier, e.g. with a statement that generates the HTML Start directive, automatically updates the skill manifest, and patches Litexa assets relative URLs.

litexa-vscode

VS Code extensions for the Litexa language that provides syntax highlighting for .litexa files. Click to learn more about the VS Code extension.

@litexa/assets-wav

A WAV/MP3 composer that can combine multiple overlapping samples into a single MP3 stream, and a binding layer for use in Literate Alexa. Click to learn more about the WAV audio converter.

Developer Setup

While having split code-bases facilitates code-sharing, it comes at a cost of increased difficulty in tracking and testing features across repositories. For this reason we've decided to organize this codebase into a multi-package repository (or monorepo).

This monorepo uses Lerna to manage all of its packages.

To get started, run npm install from the root directory of the repository. This will install the dependencies and bootstrap Lerna. Lerna bootstrap and link are called during postinstall. To learn more, check out the @learna/bootstrap documentation.

Global install from local

During development, you should install any packages you plan on modifying from the local package.

npm install -g ./packages/litexa

You can also install multiple packages at the same time:

npm install -g ./packages/litexa ./packages/litexa-apl ./packages/litexa-deploy-aws

Cleaning

It's important to get your base project to a consistent state. A utility function clean has been provided for you. It removes node_modules and re-installs them for you and the runs npx lerna clean which goes through each managed package and removes its node_modules

For more information on Lerna's clean command, check out the @learna/clean documentation.

Testing

Unit Tests

To test your package run

npx lerna run test --scope [package-your-developing]

for example, if you wanted to run test litexa and @litexa/deploy-aws you'd run

npx lerna run test --scope litexa @litexa/deploy-aws

to run all the tests, omit the scoped flag

npx lerna run test

Coverage

to run test coverage for your package(s) run

npx lerna run coverage --scoped [package-your-testing]

to run them all

npm run coverage:lerna

Integration Tests

Integration tests are handled outside of Lerna, by the unpublished @litexa/integration-tests package in the ./tests directory. If you're writing an integration test, add it there. Integration tests can also be referred to for usage examples of various Litexa features.

Misc

Note: all run does is accept an argument that it's going to use to run the npm script in your package so all npx lerna run test is doing is going through each package and running the test script from your package.json, if the script doesn't exist for a package it skips it.

For more information on the run command check out the Lerna docs.

Build

To build the entire project run

npm run build

from the root of the project directory. This command will do the following

• Remove and perform a clean install of the lerna project
• Clean all the package dependencies
• Clean all the test dependencies
• Look at all the packages, find any common dev dependencies or new packages and surface them up as shared dependencies in package.json
• Bootstrap and Hoist them for use with Lerna aka Bundle them
• And run the Coverage for the entire project

if this command succeeds, you should have fair confidence the code is in a good working state.

Documentation Website

Full documentation is available at https://litexa.com. To run the documentation website locally, please do the following.

Generate Language Reference

The parser source ./packages/litexa/src/parser/litexa.pegjs supports using block comments to document individual statements. The process of refreshing the doc website is manually done by running the command:

npm run docs:reference

Run the Website

To start the docs website in interactive/watch mode, then run this:

npm run docs:dev

The website will update with any change in the docs folder. For more info on Vuepress - https://v0.vuepress.vuejs.org/guide/#how-it-works

Build The Website for Hosting

To build the full static website for S3 or GitHub hosting, run the following to get a static render generated at docs/.vuepress/dist

npm run docs:build

Security

Security is of the utmost importance. This section will describe NPM scripts that can help with making sure that the code base is as secure as possible.

Dependency Audit

NPM provides a tool that will scan and automatically install any compatible updates to vulnerable dependencies. More on npm audit here.

To run the tool against every Litexa package, run the following from the root of the code base:

npm run audit:fix

If the tool does automatically install any compatible updates, it's advised to run npm run coverage before you commit any changes (to make sure nothing has broken in the update).