There are a few Emacs modes for SML.
http://primate.net/%7Eitz/mindent.tar, developed by Ian Zimmerman, who writes:
Unlike the widespread sml-mode.el it doesn’t try to indent code based on ML syntax. I gradually got skeptical about this approach after writing the initial indentation support for caml mode and watching it bloat insanely as the language added new features. Also, any such attempts that I know of impose a particular coding style, or at best a choice among a limited set of styles, which I now oppose. Instead my mode is based on a generic package which provides manual bindable commands for common indentation operations (example: indent the current line under the n-th occurrence of a particular character in the previous non-blank line).
Definitions and uses
There is a mode that supports the precise def-use information that MLton can output. It highlights definitions and uses and provides commands for navigation (e.g., jump-to-def, jump-to-next, list-all-refs). It can be handy, for example, for navigating in the MLton compiler source code. See EmacsDefUseMode for further information.
Building on the background
Tired of manually starting/stopping/restarting builds after editing files? Now you don’t have to. See EmacsBgBuildMode for further information.
MLton’s error messages are not among those that the Emacs next-error parser natively understands. The easiest way to fix this is to add the following to your .emacs to teach Emacs to recognize MLton’s error messages.
(require 'compile) (add-to-list 'compilation-error-regexp-alist 'mlton) (add-to-list 'compilation-error-regexp-alist-alist '(mlton "^[[:space:]]*\\(\\(?:\\(Error\\)\\|\\(Warning\\)\\|\\(\\(?:\\(?:defn\\|spec\\) at\\)\\|\\(?:escape \\(?:from\\|to\\)\\)\\|\\(?:scoped at\\)\\)\\): \\(.+\\) \\([0-9]+\\)\\.\\([0-9]+\\)\\(?:-\\([0-9]+\\)\\.\\([0-9]+\\)\\)?\\.?\\)$" 5 (6 . 8) (7 . 9) (3 . 4) 1))