Neovim

Neovim is a fork of Vim that keeps the modal editing model and the familiar configuration style while rewriting the parts underneath that had become hard to extend. It runs in a terminal, edits text through operators and motions, and reads most existing Vim configuration and plugins.

The changes that matter are structural. Lua is embedded as a configuration and plugin language beside Vimscript. A job-control mechanism and event loop let plugins run external programs without freezing the editor. A Language Server Protocol client is built into the core, so completion, diagnostics and go-to-definition work once a server is set up. Tree-sitter parses code into a real syntax tree for highlighting and structural text objects, instead of regular-expression matching. A terminal emulator runs inside a buffer.

Everything is exposed over a msgpack-RPC API, which is how graphical front-ends and embedding applications talk to it; the core has no interface of its own beyond the terminal. Out of the box it is close to bare, and the elaborate setups people show off are assembled from plugins.