Merlin
Context sensitive completion for OCaml in Vim and Emacs
...So, for instance, OCaml 4.11.* maps to branch 411. The main branch is usually synchronized with the branch compatible with the latest (almost-)released version of OCaml. Note: if you're using an older version of OCaml (between 4.02 and 4.10) you will want to build the 3.4 branch, although it won't contain the most recent features. If you want to work on merlin, you'll want to avoid the -p merlin, to build in dev mode, with some extra warnings enabled. In that case you'll also need an extra dependency.