README.org

lang/ocaml

Table of Contents

• Description
  • Module Flags
  • Plugins
• Prerequisites
• Features
• Configuration
• Appendix
  • Commands
  • Hacks

Description

This module adds OCaml support to Doom Emacs, powered by tuareg-mode.

• Code completion, documentation look-up, code navigation and refactoring (merlin)
• Type, documentation and function argument display on idle (merlin-eldoc)
• REPL (utop)
• Syntax-checking (merlin with flycheck-ocaml)
• Auto-indentation (ocp-indent)
• Code formatting (ocamlformat)
• Dune file format (dune)

Module Flags

This module provides no flags.

Plugins

• tuareg
• merlin
• merlin-eldoc
• ocp-indent
• flycheck-ocaml*
• utop*
• ocamlformat*
• dune

Prerequisites

This module has no hard dependencies, but it is recommanded that you install opam and the following opam (optional) packages:

opam install merlin utop ocp-indent dune ocamlformat

Features

• The following files should have syntax highlighting support: .ml{i,p,y,}, .eliom{i,}, jbuild, dune, opam
• merlin-mode is activated whenever a .merlin file is found (including in a parent directory) and ocamlmerlin executable is present
• Line-based auto-indentation is provided by ocp-indent, if it is available.

Configuration

• If :completion company is enabled then autocomplete is provided by merlin
• When :checkers syntax is enabled then flycheck-ocaml is activated to do on-the-fly syntax/type checking via merlin, otherwise this is only done when the file is saved.
• Spell checking is activated in comments if :checkers spell is active
• A REPL is provided if utop is installed and :tools eval is active
• If :editor format is enabled, the ocamlformat executable is available and there is an .ocamlformat file present then format-all-buffer is bound to ocamlformat, otherwise to ocp-indent
• If :editor multiple-cursors is enabled then identifiers can be refactored with v R and multiple cursors (this correctly matches identifier occurrences according to scope, it is not purely a textual match)
• If :emacs imenu is enabled then top level symbols (modules, type, functions, etc.) can be looked up using SPC / i

Run doom sync to install all packages and doom doctor to diagnose missing tools.

Appendix

Commands

Command	Key	Description
merlin-type-enclosing	<localleader> t	display type under point
tuareg-find-alternate-file	<localleader> a	switch between .ml and .mli
merlin-locate	g d	lookup definition
merlin-occurences	SPC c D	lookup references
merlin-document	K	lookup documentation
merlin-imenu	SPC s i	symbol lookup in file
merlin-iedit-occurrences	v R	visual refactor identifier under point (multiple cursors)
utop	SPC o r	open utop as REPL
utop-eval-region	SPC c e	evaluate selected region in utop

Hacks

• set-ligatures! is called with the full tuareg prettify symbol list, this can cause columns to change as certain keywords are shortened (e.g. fun becomes λ.
• tuareg-opam-update-env is called the first time tuareg is loaded