Welcome to LassoGuide

Lasso is a powerful programming language used to drive millions of web pages from servers around the world. It has an easy-to-master syntax and allows fast, flexible development and scripting. Lasso can be used in many ways, and as a language, provides a virtually infinite set of shortcuts for achieving development goals.

What follows is a living set of documentation for the Lasso programming language. As this documentation will be improved over time, please review regularly during your development and feel free to ask questions or make suggestions for improvement. Contributions and pull requests can be made at the project’s Git repository.


The previous revision of LassoGuide can be found at http://lassoguide.com/9.2/.

How to Use This Guide

This guide has many parts and is intended to cover all aspects of the Lasso programming language. Due to the comprehensive nature of this guide, the following suggestions are provided to help you get the most out of this documentation without reading every word.

  • Read most everything in the introduction, but read only the installation instructions for the OS you are using. Also, if you are just getting started, you can skim the Lasso Instance Manager and Instance Administration and Configuration chapters and come back to them when you need to.
  • After reading through Getting Started with Lasso, you should be ready to start digging into developing with Lasso. As you get up to speed, keep the Lasso Language Guide handy to familiarize yourself with the basic features and syntax.
  • Read through the chapter titles in all of the other sections to familiarize yourself with the contents of this documentation and what’s available in the language. When you find yourself needing more information about some aspect or feature of Lasso, you’ll know where to find it.

Conventions Used in This Guide

There are many code samples used throughout this guide. References to methods, types, or traits and small snippets of code inlined with other text are set in a monospace typeface, e.g. sample_method or short code snippet. References to variable names or to values will be in double quotes “like this”.

Longer blocks of sample code will be slightly offset from the surrounding text and will have syntax highlighting applied to them. The result produced by running the code will be displayed using line comments. If the result fits on one line, a line comment in the form of // => Value Produced will be used. If multiple lines are needed, the first line will just have // => while all subsequent lines will start with a line comment and space, followed by the value for that line. For example:

// Single-line value produced
2 + 3
// => 5

// Multi-line value produced
'Line one.' + '\n' + 'Line two.'

// =>
// Line one.
// Line two.

For examples involving running commands from the command line, a shell prompt ($>) will be used. Any output to standard out that is generated from the command will be shown below the command as you would see it in your terminal. For examples of issuing Lasso commands from the interactive interpreter, a Lasso prompt (>:) will be used, and any values produced from running those commands will be shown using the line comment convention as outlined above for sample code blocks.

Additional Resources

Here are some additional resources you may find useful:

Lasso Reference
Reference to the built-in types, methods, and traits.
The online Lasso community/email list is a great place to ask questions and get answers.
Methods, types, and traits created by members of the Lasso community to solve common problems.
LassoSoft Website
The latest information about Lasso.
Lasso source code repository
An SVN repository containing source code for a number of Lasso components.
LassoGuide PDF
The 9.3 version of LassoGuide in PDF format.
LassoGuide Dash docset
The current version of LassoGuide as a Dash docset.
LassoGuide source
The Git repository containing the full LassoGuide source.