Elisp code that enables syntax and type checking of Standard ML code using MLton through Flycheck.

flycheck-mlton.el

;;; flycheck-mlton.el --- Flycheck: MLton support -*- lexical-binding: t; -*-

;; This code is modified by SAITOU Keita <keita44.f4@gmail.com>.
;;
;; Original source is available here,
;; URL: http://hebiyan.hatenablog.com/entry/20160316/1458125059

;; Package-Requires: ((emacs "24.1") (flycheck "0.22") (sml-mode "0.4"))

;;; Commentary:

;;; Code:
(require 'flycheck)

(flycheck-define-checker mlton
  "Standard ML type and syntax checking with mlton compiler.
See URL 'http://mlton.org"

  :command ("mlton" "-stop" "tc" source)

  :error-patterns
  (;; <= v20130715, and EOF error in >= v20180207
   (error line-start "Error: " (file-name) (+ blank) line "." column ".\n"
          (message (1+ line-start (+ blank) (+ nonl) "\n")))
   ;; >= v20180207
   (error line-start "Error: " (file-name) (+ blank)
          line "." column "-" (+ digit) "." (+ digit) ".\n"
          (message (1+ line-start (+ blank) (+ nonl) "\n"))))
  :modes sml-mode)

(provide 'flycheck-mlton)

;;; flycheck-mlton.el ends here