OCaml (the Reason compiler) has historically had excellent (and fast) editor support tooling: Merlin.[1] That is now being packaged up as a language server (i.e

OCaml (the Reason compiler) has historically had excellent (and fast) editor support tooling: Merlin.[1] That is now being packaged up as a language server (i.e., LSP).[2] Once you try a Merlin-based editor addon, everything else will seem dog-slow. [1] https://github.com/ocaml/merlin https://github.com/ocaml/merlin [2] https://github.com/ocamllabs/vscode-ocaml-platform https://github.com/ocamllabs/vscode-ocaml-platform