spacemacs/layers/+lang/ocaml/README.org

Ocaml layer

• Description
  • Features:
• Install
  • Layer
  • Using merlin for error reporting
  • OPAM packages
  • Enabling formatting on save
• Key bindings
  • REPL (utop)
  • Dune
• layer improvements list

Description

This is a very basic layer for editing ocaml files.

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

Install

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.

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 ... )

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

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)

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 d	Case analyze the current enclosing
SPC m t p	Dune run tests and promote.
SPC m t P	Dune promote.

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

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.

TODO layer improvements list

1. Add more proper spacemacs key bindings for basic merlin tasks
2. Add proper key bindings for ocamldebug
3. Add more key bindings for tuareg-mode