Erlang, If You See What I Mean

gistfile1.sls

(define-language model-erlang
  (world ((module ...) (actor ...)))

  (module-dictionary (module ...))

  (module (atom ;; module name
	   (atom value) ...)) ;; (constant-name constant-definition) - incl functions

  (atom string)

  (actor (pid (message ...) (link ...) (monitor ...) process))

  (pid variable-not-otherwise-mentioned)
  (message any)
  (link pid)
  (monitor (pid ref))
  (ref variable-not-otherwise-mentioned)

  (process (module ;; current active module
	    expr))

  (value number
	 atom
	 (fun (variable ...) expr))

  (expr value
	variable
	(call (expr expr) expr ...) ;; module:fun(arg, ...)
	(call expr expr ...) ;; fun(arg, ...)
	(send expr expr)
	(receive (variable) expr)
	(spawn expr))

  (context hole
	   (call (context expr) expr ...)
	   (call (value context) expr ...)
	   (call (value value) value ... context expr ...)
	   (call context expr ...)
	   (call value value ... context expr ...)
	   (send context expr)
	   (send value context)))