Gene is a one man show and he added JS, Python, etc scripting all at once. At the same time, he was busy documenting the C# functionality, which is now pretty good. I'd agree that having a reference would be helpful for the other languages, though. When I started working with HG there was no C# reference either and it was painful to use the existing scripts as a guide since everything was not covered. Unfortunately, I don't know those other languages beyond a couple short classes taken years ago. Either way, I'm sure you need the reference for specific commands so my minimal experience wouldn't help anyway. My suggestion would be to file a feature request to get documentation added for those other languages.