> As far as I know, there is no other editor with this capability. Well, to some degree Vim can do this too. It doesn't let you "eval" a function you just type

> As far as I know, there is no other editor with this capability. Well, to some degree Vim can do this too. It doesn't let you "eval" a function you just typed into a buffer, but it can eval a vimscript file that you just edited. Including the vimrc, but just like Emacs' init.el reloading it doesn't actually reset the state. But where Vim can't just eval a whole function you can write very complex keybindings on the fly in a much simpler syntax, which made up for it in a few situations for me. And it's very similar in how the configuration and plugins work - it's all just a scripting language spread across files, and instead of having separately developed plugins you just write a function and run it, more or less. Emacs is more flexible still, but with its own quirks.