Introducing Gopcaml mode - structural OCaml editing - Community - OCaml

Hi all, I am pleased to announce the first release of Gopcaml-mode, a new emacs library that aims to extend the existing OCaml editing experience with structural editing capabilities.

A picture is worth a thousand words, so I’ll cut to the chase, and start with a few demonstrations:

Examples

• AST-based code navigation - C-M-n, C-M-p, C-M-u, C-M-d, C-M-f, C-M-b

ast-code-navigation752×455

• AST-based code transformation -C-M-N, C-M-P, C-M-F, C-M-B

ast-code-transform752×455

• Mark exp - C-M-SPC

• Extract expression into letdef - C-c C-e

This is just a small sample of the features - a full listing is provided at the project readme, which can be found at the project page 114.

Notes

This plugin is quite faithful to the OCaml specification and doesn’t reimplement a separate OCaml parser as some other plugins do - instead I use the Ecaml package (which allows interfacing with Emacs from OCaml code) to allow delegating to the OCaml parser (from Ocaml-compiler-libs) directly.

It’s in the process of being published to opam, and should be available to download soon.

Edit: It has now been merged into the opam-repositories and can be installed via opam:

Installation

• Install the package from opam

opam install gopcaml-mode

• load the package in your init.el

 (let ((opam-share (ignore-errors (car (process-lines "opam" "config" "var" "share")))))
	   (when (and opam-share (file-directory-p opam-share))
	     ;; Register Gopcaml mode
	     (add-to-list 'load-path (expand-file-name "emacs/site-lisp" opam-share))
         (autoload 'gopcaml-mode "gopcaml-mode" nil t nil)
	     ;; Automatically start it in OCaml buffers
	     (setq auto-mode-alist
		   (append '(("\\.ml[ily]?$" . gopcaml-mode)
			     ("\\.topml$" . gopcaml-mode))
			   auto-mode-alist))
	     ))

• (Optional) install multiple-cursors to enable extraction and smartparens for better handling of parenthesis.