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SyntaxErl

SyntaxErl is a syntax checker tool for Erlang. The syntax checker currently supports erlang source files (.erl), erlang header files (.hrl), erlang configs (.config, .rel, .script, .app, .app.src), escript files (.erl, .escript, .es), leex files (.xrl), and yecc files (.yrl). Its main purpose is to be used by tools like Emacs's Flymake and Vim's Syntastic or ALE.

SyntaxErl uses rebar, rebar3 or erlang.mk configs under the hood to determine deps and libs paths. Some common compile options are hardcoded, while others project specific are read from the config files. For the syntax checker to work correctly, make sure that your project is compilable and all the deps are at their places.

Building

Information on building and installing Erlang/OTP can be found here (more info).

Dependencies

To build SyntaxErl you will need a working installation of Erlang, git, and GNU make.

Building SyntaxErl

$ git clone git://github.com/ten0s/syntaxerl.git
$ cd syntaxerl
$ make

After performing the steps above in the current working directory you now have a script called `syntaxerl'. Place this script anywhere in your path.

Usage

Command line

$ syntaxerl
Syntax checker for Erlang (0.16.0)
Usage: syntaxerl [-d | --debug] <FILENAME>
       syntaxerl <-h | --help>
  -d, --debug    Enable debug output
  -h, --help     Show this message

Emacs

Flymake

;;;----------------------------------------
;;; erlang-mode
;;;----------------------------------------

(setq erlang-root-dir "/opt/r16b03-1")
(setq load-path (cons (car (file-expand-wildcards (concat erlang-root-dir "/lib/tools-*/emacs"))) load-path))
(setq erlang-electric-commands nil)
(require 'erlang-start)

(add-hook 'erlang-mode-hook
  '(lambda()
     (imenu-add-to-menubar "Imenu")))

; define auto erlang mode for these files/extensions.
(add-to-list 'auto-mode-alist '(".*\\.app\\'"     . erlang-mode))
(add-to-list 'auto-mode-alist '(".*app\\.src\\'"  . erlang-mode))
(add-to-list 'auto-mode-alist '(".*\\.config\\'"  . erlang-mode))
(add-to-list 'auto-mode-alist '(".*\\.rel\\'"     . erlang-mode))
(add-to-list 'auto-mode-alist '(".*\\.script\\'"  . erlang-mode))
(add-to-list 'auto-mode-alist '(".*\\.escript\\'" . erlang-mode))
(add-to-list 'auto-mode-alist '(".*\\.es\\'"      . erlang-mode))
(add-to-list 'auto-mode-alist '(".*\\.xrl\\'"     . erlang-mode))
(add-to-list 'auto-mode-alist '(".*\\.yrl\\'"     . erlang-mode))

; add include directory to default compile path.
(defvar erlang-compile-extra-opts
  '(bin_opt_info debug_info (i . "../include") (i . "../deps") (i . "../../") (i . "../../../deps")))

; define where put beam files.
(setq erlang-compile-outdir "../ebin")

;;;----------------------------------------
;;; flymake
;;;----------------------------------------

(require 'flymake)
(require 'flymake-cursor) ; http://www.emacswiki.org/emacs/FlymakeCursor
(setq flymake-log-level 3)

(defun flymake-compile-script-path (path)
  (let* ((temp-file (flymake-init-create-temp-buffer-copy
                     'flymake-create-temp-inplace))
         (local-file (file-relative-name
                      temp-file
                      (file-name-directory buffer-file-name))))
    (list path (list local-file))))

(defun flymake-syntaxerl ()
  (flymake-compile-script-path "~/bin/syntaxerl"))

(add-hook 'erlang-mode-hook
  '(lambda()
     (add-to-list 'flymake-allowed-file-name-masks '("\\.erl\\'"     flymake-syntaxerl))
     (add-to-list 'flymake-allowed-file-name-masks '("\\.hrl\\'"     flymake-syntaxerl))
     (add-to-list 'flymake-allowed-file-name-masks '("\\.xrl\\'"     flymake-syntaxerl))
     (add-to-list 'flymake-allowed-file-name-masks '("\\.yrl\\'"     flymake-syntaxerl))
     (add-to-list 'flymake-allowed-file-name-masks '("\\.app\\'"     flymake-syntaxerl))
     (add-to-list 'flymake-allowed-file-name-masks '("\\.app.src\\'" flymake-syntaxerl))
     (add-to-list 'flymake-allowed-file-name-masks '("\\.config\\'"  flymake-syntaxerl))
     (add-to-list 'flymake-allowed-file-name-masks '("\\.rel\\'"     flymake-syntaxerl))
     (add-to-list 'flymake-allowed-file-name-masks '("\\.script\\'"  flymake-syntaxerl))
     (add-to-list 'flymake-allowed-file-name-masks '("\\.escript\\'" flymake-syntaxerl))
     (add-to-list 'flymake-allowed-file-name-masks '("\\.es\\'"      flymake-syntaxerl))

     ;; should be the last.
     (flymake-mode 1)
))

; see /usr/local/lib/erlang/lib/tools-<Ver>/emacs/erlang-flymake.erl
(defun erlang-flymake-only-on-save ()
  "Trigger flymake only when the buffer is saved (disables syntax
check on newline and when there are no changes)."
  (interactive)
  ;; There doesn't seem to be a way of disabling this; set to the
  ;; largest int available as a workaround (most-positive-fixnum
  ;; equates to 8.5 years on my machine, so it ought to be enough ;-) )
  (setq flymake-no-changes-timeout most-positive-fixnum)
  (setq flymake-start-syntax-check-on-newline nil))

(erlang-flymake-only-on-save)

Erlang-flymake

Your help is welcome.

Vim

Syntastic

Setup everything as described here. Then add

let g:syntastic_erlang_checkers=['syntaxerl']

to your vimrc.

Thanks locojay for that.

ALE

Install ALE plugin for vim 8+ or neovim.

To disable erlc linter please add the following lines to your vimrc:

let g:ale_linters = {
\   'erlang': ['syntaxerl'],
\}