This is something I whipped together to make editing Emily files in Emacs a bit nicer.

emily.el

;; major mode for the emily programming language
;;
;; by erik osheim
;;
;; project at: https://bitbucket.org/runhello/emily
;; see emily/doc/manual.md for more information.

;; TODO:
;; 1. indentation support
;; 2. special support for definitions (e.g. f ^x = x + 1)
;; 3. beef up symbol table support
;; 3. consider highlighting delimiters/symbolic operators
;; 4. repl integration?
;; 5. ??????

(defvar emily-mode-hook nil)

(defvar emily-mode-map
  (let ((map (make-sparse-keymap)))
    (define-key map "\C-j" 'newline-and-indent)
    map)
  "Keymap for Emily major mode")

(add-to-list 'auto-mode-alist '("\\.em\\'" . emily-mode))

(defconst emily-font-lock-keywords-1
  (list
   `(,(regexp-opt '("while" "tern" "return" "loop" "let" "if" "each" "do") t) . font-lock-builtin-face))
  "Minimal highlighting expressions for Emily mode")

(defconst emily-font-lock-keywords-2
  (append
   emily-font-lock-keywords-1
   (list
    `(,(regexp-opt '("true" "null") t) . font-lock-constant-face)
    `(,(regexp-opt '("this" "current") t) . font-lock-keyword-face)))
  "Additional Keywords to highlight in Emily mode")

(defconst emily-font-lock-keywords-3
  (append
   emily-font-lock-keywords-2
   (list
    `(,(regexp-opt '("xor" "times" "thisUpdate" "thisTransplant" "thisInit" "thisFreeze" "set" "println" "print" "or" "nullfn" "not" "negate" "minus" "lte" "lt" "ln" "has" "gte" "gt" "eq" "divide" "append" "and" "add") t) . font-lock-keyword-face)))
  "Full highlighting in Emily mode")

(defvar emily-font-lock-keywords emily-font-lock-keywords-3
  "Default highlighting expressions for Emily mode")

(defvar emily-mode-syntax-table
  (let ((st (make-syntax-table)))
    (modify-syntax-entry ?( "(" st)
    (modify-syntax-entry ?) ")" st)
    (modify-syntax-entry ?{ "(" st)
    (modify-syntax-entry ?} ")" st)
    (modify-syntax-entry ?[ "(" st)
    (modify-syntax-entry ?] ")" st)
    (modify-syntax-entry ?# "<" st)
    (modify-syntax-entry ?\n ">" st)
    (modify-syntax-entry ?\r ">" st)
    st)
  "Syntax table for emily-mode")

(defun emily-mode ()
  "Major mode for editing Workflow Process Description Language files"
  (interactive)
  (kill-all-local-variables)
  (set-syntax-table emily-mode-syntax-table)
  ;;(use-local-map emily-mode-map)
  (set (make-local-variable 'font-lock-defaults) '(emily-font-lock-keywords))
  ;;(set (make-local-variable 'indent-line-function) 'emily-indent-line)
  (setq major-mode 'emily-mode)
  (setq mode-name "Emily")
  (run-hooks 'emily-mode-hook))

(provide 'emily)