litexa

Litexa [archived]

A literate style programming language and toolchain for building long form Alexa skills

🔔 Final Update

As of April 2023, we've updated dependencies to catch up with the latest security patches. With that, we're ending our 4 year journey with Litexa and deprecating the official distribution on GitHub and npm. The repository will remain accessible, and we will leave this site and documentation up for a while as an archive for those who still use it. A big thank you to everyone who built exciting Alexa skills with Litexa!

See all updates  →

The Language

Purpose built for writing Alexa skills, succinct syntax gives you language level support for defining state machines that turn incoming voice requests into rich responses. Built-in statements handle composing SSML speech, displaying screens, creating directives, and adding variations to your flow and delivery.

Read the full Language Specification  →
launch
  say "Hi there!"
    or "<!Howdy.>"
    or "Greetings, human."
  say "What's your name?"

  when "(my|the) name is $name"
    or "(you can|you should|) call me $name"
    with name = AMAZON.US_FIRST_NAME
    say "Hey! nice to meet you, $name."
    soundEffect happy.mp3

# The Compiler

Emits standard, highly performant JavaScript code ready to deploy to a host like AWS Lambda. Compile time checking of things like language model elements and asset references means fewer bugs to discover at runtime.

# The Toolchain

A one-step build and deploy system that seamlessly synchronizes your language model and deploys your skill endpoint, assets, and storage to AWS.

# Extensions

Designed to be tweaked, Litexa extensions let you add new features to the compiler and toolchain, even add new syntax. Build tools to dig into what makes your team and project special.

State Management

Litexa's syntax is designed around the central idea of handling incoming intents based on the user's current state.

Learn more about State Management  →
askAboutRoses
  say "Do you prefer red or blue roses?"
  LISTEN microphone

  when "I like $color roses"
    or "$color ones"
    or "$color"
    with color = "red", "blue"

  say "Hey, I like $color ones too."
    or "Nice! I like $color ones too."
  END

 when AMAZON.RepeatIntent
  -> askAboutRoses

Variables & JS Interpolation

Litexa variables can be easily persisted and retrieved between skill launches, and resolved request slot values are handled seamlessly. Additionally, JavaScript interpolation is effortless: JS values (including objects, arrays, and functions) can be directly accessed from within Litexa.

Read the Variables and Expressions documentation  →
# main.litexa
launch
  if @name
    say "Welcome back, @name."
    -> playGame
  else
    -> askName

askName
  say "What's your name?"

  when "My name is $name"
    with $name = AMAZON.US_FIRST_NAME

    say "Hi, {formatName($name)}"
    # store the result permanently
    @name = $name

// litexa/main.js
function formatName(name) {
  return `the most honorable ${name}`;
}

Screen Devices

For Alexa-enabled devices with a screen, Litexa supports easily building, sending, and validating both Alexa Presentation Language (APL) and Display.RenderTemplate directives.

Read the Screens documentation  →
apl
  document: apl_doc.json
  data: apl_data.json
  commands: apl_commands.json

say "turning page"
apl
  commands: turn_page.json

soundEffect page_chime.mp3
say "page turned"

# Install, Generate, Test, and Deploy

# install
npm install -g @litexa/core
npm install -g @litexa/deploy-aws

# generate a skill
mkdir mySkill
cd mySkill
litexa generate

# test your skill locally
litexa test

# deploy to aws
litexa deploy

# Does Litexa's deprecation mean my skills will stop working?

No! You can still use Litexa to generate and deploy new builds of your skills, and your existing skill deployments will be unaffected. This official repository and the npm package is deprecated, so no further patches or updates will happen, but you are free to fork it and update it as you see fit for your projects.

# How much does Litexa cost? Where does it come from?

Litexa is free!

Litexa is an Alexa Labs community-supported project (alpha) from the Alexa Games team at Amazon. We (Alexa Games) have used Litexa to develop and ship 20+ Alexa skills, your mileage may vary. Your feedback is welcome and we are happy to consider contributions. Otherwise, you are free to use and modify this software as needed. As with all open-source packages, please use them in accordance with the licenses assigned to each package.

For officially supported skill development tools, look for tools in the Alexa Skills Kit (opens new window) like Skill Flow Builder (opens new window) and the ASK SDK (opens new window).

# Does Litexa handle Alexa feature X?

Check out The Book to find Alexa features that Litexa supports with unique syntax. Don't see something you want to use? No sweat, Litexa has syntax to let you emit any arbitrary directive, and accept any incoming event, so no Alexa feature is inaccessible. Have a great idea for new Litexa syntax? Let us know!

# Can I still use my JavaScript libraries?

Yes! Litexa compiles into a JavaScript closure that you can inject code into, in order to add symbols that will be visible to your Litexa code. In there you can refer to any external modules in the usual way, and thereby pass their symbols up to Litexa too.

# I really like writing in TypeScript/CoffeeScript can I still do that?

Hey, actually we do too! Beyond a certain level of complexity, it's nice to split up your presentation code from your business logic, and the Litexa/JavaScript boundary is a great fit for that. The litexa generate command has a series of options, including primary code language and bundling strategy, that will help you jump right in.

# Why a language?

We just really care about syntax, and getting any boilerplate out of the way so that we're as close as we can be to just iterating on content.

# Can I make any kind of Alexa skill with Litexa?

You know, we've mostly made games with it, so we can't say for sure. We'd very much love to hear about your experiences if you try something else though. Feel free to submit a pull request if you need something to change!

# Does Litexa cover all Alexa functionality?

Litexa core is concerned with basic request routing and response generation. It has syntax to let you respond to arbitrary events, generate arbitrary directives, and inject custom JavaScript code to access any Alexa feature. Additional high level functionality is provided as Litexa extensions, optional npm modules that add new syntax and runtime functionality.

Brought to you with ❤ by the Alexa Games team at Amazon. © 2023, Amazon.com, Inc. or its affiliates. All Rights Reserved.