Support for semantic highlighting

[voneiden]

Intellij supports semantic highlighting, however it requires some (?) effort from language plugins to enable it. Semantic highlighting assigns random colors from a color gradient to local variables.

I'm unfamiliar with plugin development so I don't have any answers, but I dug up some samples on how it was implemented for other languages which could maybe serve as some kind of starting point:

• Kotlin https://github.com/JetBrains/intellij-kotlin/commit/5315f4d9da3dd56ebb7b7fedc66895969e0c7a2e
• Python https://github.com/JetBrains/intellij-community/commit/6da28521a59948d12976207b372620b765cacb69
• C/C++ https://github.com/JetBrains/intellij-community/commit/d15df0d7479213569d984f6a17be923aa34a1128
• JSON https://github.com/JetBrains/intellij-community/commit/256c9b5885777a6ede265eb3932f8f30c03d5534

To get an idea how it fits with Haskell, Haskell Code Explorer has semantic highlighting.

[rikvdkleij]

Thanks for reporting and the pointers!

Also on the todo list :smile: