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There is a VS code plugin that gives diagnostics, completion suggestions, and allows you to register rulesets with a pico engine.
It can be found here.
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Textmate Grammar
There is a textmate grammar which the majority of editors/IDEs can use to provide basic syntax highlighting. It can be found here.
KRL Language Server
There is an experimental language server for KRL that can be found here. A language server allows a single code base to be used for features like completion, diagnostics, etc. for any IDE that can communicate with it. If you would like to build support for your IDE you can use this to easily bootstrap the majority of features. You could google “<your IDE here> language server client” for instructions on how to connect your IDE to the server. Read more about language servers here.
Testing Tools
Python module for interacting with Picos: https://github.com/hitch-b24/picosapi/wiki from Braden Hitchcock
Additional Notes
If you happen to create any additional tooling for KRL please contact Phil Windley or another member of Pico Labs so we can add that here!