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LK (Language Kit) is a simple but powerful scripting language that is designed to be small, fast, and easily embedded in other applications. The core LK engine, including lexical analyzer, parser, compiler, and virtual machine is only dependent on the Standard C++ Library (STL), making it extremely lightweight and portable.
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LK is a scripting language originally developed for the National Renewable Energy Laboratory's System Advisor Model (SAM). LK is designed to be small, fast, and easily embedded in other applications, and provides a way for users to to extend an application's built-in functionality.

This repository contains a cross-platform standard library of function calls and core LK engine, which includes a lexical analyzer, parser, compiler, and virtual machine. It comprises roughly 7000 lines of ISO-standard C++ code, and is only dependent on the Standard C++ Library (STL), making LK extremely tight and portable to various platforms. LK also provides a C language API for writing extensions that can be dynamically loaded at runtime.

LK can utilize standard 8-bit ASCII strings via the built-in std::string class, or can be configured to utilize an std::string-compliant string class from an external library. In this way, Unicode text can be supported natively. For example, direct integration and linkage with the wxWidgets C++ GUI library string class is provided as an option.

Running LK Scripts

LK is designed to be integrated into other applications to add functionality to those applications.

The WEX project includes the lkscript program, which is a stand-alone application that can be used to write and run LK scripts.

The System Advisor Model includes LK script, and integrates the WEX lkscript program in its user interface.

LK Language Documentation

The documentation of the LK language is written in LaTeX:


Please check out ( to get started.

If you have found an issue with LK or would like to make a feature request, please let us know by adding a new issue on the issues page.

If you would like to submit code to fix an issue or add a feature, you can use GitHub to do so. The overall steps are to create a fork on using the link above, and then install GitHub on your computer and use it to clone your fork, create a branch for your changes, and then once you have made your changes, commit and push the changes to your fork. You can then create a pull request that we will review and merge into the repository if approved.


LK is licensed under a BDS-3-Clause license.

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