Well, every IDE is designed to be extended. Unfortunately neither Go nor Rust are really intended for the extension use case. Sublime Text supports Python scripting but isn't an IDE.<p>I think the best IDE scripting experience I know of right now is IntelliJ (or other Jetbrains IDEs) with the Live Plugin extension. You can write simple scripts in Kotlin or Groovy. They're similar langs but the latter is dynamically typed. And then you can just do things like register menu items, explore the language AST, edit buffers, trigger refactorings, access remote machines. Anything, really.<p>As your script gets too big, you just convert it to a 'real' plugin project with multiple files, can use libraries, etc.<p>Then you can upload it to the Marketplace so people can find it.<p>And if your plugin ends up being really good, Jetbrains run a monetization system so you can sell it easily. They handle all the billing, tax, licensing etc for you, so you can focus on your plugin.<p>It's pretty rad. That said, in years of working with IntelliJ I never felt a need to extend it for my own personal use. It's not like emacs where every user ends up with piles of elisp. The defaults are pretty good, and many features where in other IDEs you'd be forced to write a script can be done entirely via the GUI. For example if you want to define templates that auto-expand and where the cursor moves between 'slots', you can do that using a mini templating language without needing to do any coding. There's a thing called Structural Search & Replace which is similar - it lets you create templates that match against ASTs and do transforms on them.