liquid.el

;;; NOTES:
;;;   - two syntax matching types:
;;;     1) "regex" . font-lock-name
;;;     2) "regex" (capture-group-id font-lock-name)
;;;   - variable name regex: \\(?:\\w\\|\\.\\|_\\)+
;;;
;;; TODO:
;;;   - strings can be in single quotes
;;;   - detect string vs. object value types
;;;   - detect boolean operators (and|or)
;;;   - add groups for cycle tags
;;;   - for: 
;;;     - add limit:n, offset:n
;;;     - add reversed
;;;     - add support for ranges

(setq liquidKeywords
      '(
	;;; core stuff
	("{%\\|%}\\|{{\\|}}" . font-lock-comment-face) ;;; liquid tag delimiters					
	("{%\s*\\(assign\\|capture\\|endcapture\\|for\\|endfor\\|if\\|endif\\|comment\\|endcomment\\|else\\|elsif\\|unless\\|endunless\\|case\\|when\\|endcase\\|cycle\\)" (1 font-lock-keyword-face)) ;;; liquid construct tags       					
	("forloop" . font-lock-keyword-face)
	("forloop.\\(length\\|index0\\|index\\|rindex0\\|rindex\\|first\\|last\\)" (1 font-lock-variable-name-face))
	("{%\s*\\(?:assign\\|capture\\|for\\|if\\|unless\\|case\\|when\\)\s+\\(\\(?:\\w\\|\\.\\|_\\)+\\)" (1 font-lock-variable-name-face)) ;;; variable after assign|capture|for|if

	("{{\s*\\(\\(?:\\w\\|\\.\\)+\\)" (1 font-lock-variable-name-face)) ;;; variable/object being outputted

	;;; filter stuff (hack, only supports 2 chained filters)
	("\s+|\s+" . font-lock-comment-face) ;;; liquid tag delimiters					
	("{{\s*\\(?:\\w\\|\\.\\)+\s+|\s+\\(\\w+\\)" (1 font-lock-type-face)) ;;; variable after assign|capture|for|if
	("{{\s*\\(?:\\w\\|\\.\\)+\s+|\s+\\w+\s+|\s+\\(\\w+\\)" (1 font-lock-type-face)) ;;; variable after assign|capture|for|if

	;;; if/else stuff
	("{%\s*\\(?:if\\|unless\\)\s+\\(?:\\w\\|\\.\\)+\s+\\(contains\\|>\\|<\\|==\\|!=\\)" (1 font-lock-keyword-face)) ;;; liquid operators	

	;;; for loop stuff
	("{%\s*for\s+\\w+\s+\\(in\\)" (1 font-lock-keyword-face)) ;;; the 'in' in "for temp in collection"
	("{%\s*for\s+\\w+\s+in\s+\\(\\(?:\\w\\|\\.\\|_\\)+\\)" (1 font-lock-variable-name-face)) ;;; the 'collection' in "for temp in collection"
	)
      )
(define-derived-mode liquid-mode html-mode
  (setq font-lock-defaults '(liquidKeywords))
  (setq mode-name "liquid mode")
  )