Otherwise it really doesn't improve on a text editor. All of these things would require a ton of work, so I stick with Sublime for now. Text isn't that bad.
IDEs are kinda close, but I've yet to see one that could effectively work with dynamic languages. RubyMine is interesting-looking, but seems to want to impose a lot of its opinions on your workflow. I don't really see how RubyMine would really be that much better than Sublime and a terminal.
It lets you build a language and an editor that forces you to follow the syntax and semantics of your language. Pro tip: Your language can be based on java :)
BTW, I don't know much about building IDEs, so I won't analyze code by myself and let the editor recognize the code. Could be very tough work.
It's totally free and open source. I was a hard core JetBrains user but vscode has been amazing. They even got minimap like sublime in last release.
Every month they move at an amazing velocity working on features devs ask for. I feel it's the modern democratic IDE
That said, it's not the perfect text editor. I don't know that it really imposes any particular workflow (beyond obvious requirements like having access to the libraries you require), but there are certainly many things that you can do in Sublime that aren't going to work in RubyMine.
Not surprisingly the first thing I did when I arrived at PARC in 1984 was write an Emacs for Interlisp.
That is a hard nut to crack, a dynamic language will frustrate static analysis.