Ocaml layer

Table of ContentsClose

1. Description
- 1.1. Features:
2. Install
3. Key bindings
- 3.1. REPL (utop)
- 3.2. Dune
4. TODO layer improvements list

1. Description

This is a very basic layer for editing ocaml files.

1.1. Features:

Syntax highlighting (major-mode) via tuareg-mode
Error reporting, completion and type display via merlin
auto-completion with company mode via merlin
syntax-checking via flycheck-ocaml (or alternatively merlin)
dune file syntax highlighting and template insertion via dune-mode
Automatic formatting via ocamlformat

2. Install

2.1. Layer

To use this configuration layer, add it to your ~/.spacemacs. You will need to add ocaml to the existing dotspacemacs-configuration-layers list in this file.

2.2. Using merlin for error reporting

By default flycheck-ocaml is used for error reporting when the syntax-checking layer is also enabled as this is common throughout spacemacs. You can disable this and switch back to merlin's default error reporting method by adding flycheck-ocaml to your excluded packages list in .spacemacs:

dotspacemacs-excluded-packages '(... flycheck-ocaml ... )

2.3. OPAM packages

This layer requires some opam packages:

merlin for auto-completion
utop
ocp-indent
ocamlformat for auto-formatting

To install them, use the following command:

opam install merlin utop ocp-indent ocamlformat

Make sure opam is initialized and configured.

opam init
opam config setup -a

2.4. Enabling formatting on save

To enable automatic formatting on save with ocamlformat, set the layer variable ocaml-format-on-save, e.g.,

(ocaml :variables ocaml-format-on-save t)

3. Key bindings

Key binding	Description
`SPC m =`	Indent buffer.
`SPC m c c`	Compile
`SPC m c p`	Check .merlin for errors
`SPC m c r`	Refresh changed .cmis in merlin
`SPC m e C`	Check for errors in current buffer
`SPC m e n`	Jump to next error
`SPC m e N`	Jump back to previous error
`SPC m g a`	Switch ML <-> MLI
`SPC m g b`	Go back to the last position where the user did a locate
`SPC m g g`	Locate the identifier under point (same window)
`SPC m g G`	Locate the identifier under point (different window)
`SPC m g i`	Prompt for module name and switch to ML file
`SPC m g I`	Prompt for module name and switch to MLI file
`SPC m g l`	Prompt for identifier and locate
`SPC m g o`	List occurrences for identifier under point
`SPC m h h`	Document the identifier under point
`SPC m h t`	Highlight identifier under cursor and print its type
`SPC m h T`	Prompt for expression and show its type
`SPC m r c`	Construct expression at hole (_) based on its type
`SPC m r d`	Case analyze the current enclosing
`SPC m t p`	Dune run tests and promote.
`SPC m t P`	Dune promote.

3.1. REPL (utop)

Key binding	Description
`C-j`	(in REPL) next item in history
`C-k`	(in REPL) previous item in history
`SPC m s b`	Send buffer to the REPL
`SPC m s B`	Send buffer to the REPL and switch to the REPL in `insert state`
`SPC m s i`	Start a REPL
`SPC m s p`	Send phrase to the REPL
`SPC m s P`	Send phrase to the REPL and switch to the REPL in `insert state`
`SPC m s r`	Send region to the REPL
`SPC m s R`	Send region to the REPL and switch to the REPL in `insert state`

3.2. Dune

Key binding	Description
`SPC m c c`	Compile.
`SPC m i a`	Insert `alias` stanza.
`SPC m i c`	Insert `copyfiles` stanza.
`SPC m i d`	Insert ignored subdirs stanza.
`SPC m i e`	Insert `executable` stanza.
`SPC m i i`	Insert `install` stanza.
`SPC m i l`	Insert `library` stanza.
`SPC m i m`	Insert `menhir` stanza.
`SPC m i p`	Insert `ocamllex` stanza.
`SPC m i r`	Insert `rule` stanza.
`SPC m i t`	Insert `tests` stanza.
`SPC m i v`	Insert `env` stanza.
`SPC m i x`	Insert `executables` stanza.
`SPC m i y`	Insert `ocamlyacc` stanza.
`SPC m t p`	Dune run tests and promote.
`SPC m t P`	Dune promote.

4. TODO layer improvements list

Add more proper spacemacs key bindings for basic merlin tasks
Add proper key bindings for ocamldebug
Add more key bindings for tuareg-mode