RedOnion

All scripting is managed in our main user interface, called LiveRepl.

Managing Scripts

Scripts are currently stored in GameData/RedOnion/Scripts.

Scripts that we bundle as example scripts appear in a zipfile, GameData/RedOnion/Scripts.zip, and will appear in the list of scripts in-game, but any scripts in Scripts.zip will be hidden by any scripts you create of the same name. If you modified an example script and want to access the unmodified version, you can rename your modified version or delete it and the example script will show up again.

Scripting Languages

We have two scripting languages, Kerbalua, and ROS (Red Onion Script). Kerbalua is a Lua implementation, while ROS is a custom language. ROS is designed to make programming easier by requiring very little syntax (examples: python-like indentation to mark program structure, and function calls/definitions without parenthesis).

Scripts are currently stored in GameData/RedOnion/Scripts, our own scripts are packed inside GameData/RedOnion/Scripts.zip. You can override our scripts simply by opening them in REPL and saving the modified version (which will become a file outside of the zip).

Autorun

Both languages can make use of Autorun to automatically load a list of scripts every time the engine gets reset. Which happens when you click the Reset Engine button, and whenever you switch to a different game scene.

You can access ksp.HighLogic.LoadedScene to get the enum of the current scene and compare it with any of the scenes in ksp.GameScenes. So for the editor (SPH or VAB), you can check ksp.HighLogic.LoadedScene==ksp.GameScenes.EDITOR.

For FLIGHT you can check ksp.HighLogic.LoadedScene==ksp.GameScenes.FLIGHT.

Note that ksp.HighLogic.LoadedScene is an enum value. If you compare it to a string (ksp.HighLogic.LoadedScene=="EDITOR") it will always return false. You need to compare it to one of the enum values in ksp.GameScenes.

This will allow you to make your autorun scripts do different things depending on which scene you are in.

Multithreading

Both engines allow you to run multiple programs at a time. And in version 0.5.0, the LiveRepl is no longer disabled when you run a script.

Intellisense

Both languages provide intellisense. It is very useful and fun to use.

However, since both languages are dynamic, it’s not possible to always guess correctly what type of return value there is from a CLR function because we cannot know from looking at the source which overload will be used, as that requires knowledge of the types of the arguments we will pas it, but we won’t have them until we actually execute the code.

Furthermore, the intellisense does not even handle every case that it could handle. Kerbalua intellisense at least, doesn’t even try to narrow down the possibilities in the case of overloads based on number of arguments to the function. This may change in the future.

Usually overloaded functions return the same type, but they are technically not required to, so you may get situations where the intellisense will not give you the right answer for that reason.

Another issue you might run into is when intellisense runs into types that are a certain base class where you would expect intellisense results for the derived class, but you instead just get results for the subclass.

Example:

ship.native.parts[1].Modules[0].

If the second part on the ship is a parachute, the zeroth module might be the ParachuteModule. However, current intellisense for lua will return results for the class PartModule, instead of ParachuteModule.

If you want to do intellisense on the actual ParachuteModule you can first assign it to another global variable.

para=ship.native.parts[1].Modules[0]
para.

Limitations

Calls to long running CLR code are not interruptible.
You cannot safely pass a function to something like List.Foreach(fn) because we cannot interrupt the Foreach call. So the entire iteration would have to occur in one KSP FixedUpdate and it would pause the game to complete. Our scripting languages have functionality for iterating over CLR collections which is interruptible, so you will have to use that instead. There’s a convenient way to iterate over dotnet collections in both Kerbalua and ROS
The CLR objects in the KSP API that you might access using ksp. or native., may be poorly documented. For some api features, modders had to expend a lot of effort to figure out how they work and how to avoid problems.

Scripting Links

Common API - An API of useful functionality that is consistent between Lua and ROS. Entries marked with [Unsafe] lead to objects from KSP, Unity, or just general CLR objects that one should be careful with. Some objects in this API, like the global ship, have been created to act as safe versions of native objects. In this case, ship is a safe version of KSP’s Vessel. The corresponding native Vessel object can be accessed using ship’s native field.

Red Onion Script (ROS) - A powerful in-game scripting engine taking inspiration from several popular languages (Ruby,Python,Javascript,etc)

Kerbalua - A Lua scripting engine implemented using MoonSharp.

Red Onion UI - A WIP UI Library, intended to be used by modders, users, and ourselves.