(module ns-state-stx mzscheme
  (require (lib "match.ss")
           "ns-utils.ss"      ;; lookup not-found
           "rpn.ss"           ;; rpn-compiler-stx
           "rpn-runtime.ss")  ;; state-lift

  (require-for-syntax "rpn-tx.ss")  ;; state-represent/find
  
  (provide ns-state-stx)

  ;; See base-stx.ss for more info.

  
  ;; The state syntax uses two lists of namespaces. The first one
  ;; contains state words, the second one normal functions that will
  ;; be automatically lifted. This function creates an 'find' method
  ;; to be plugged into 'state-represent' syntax defined in rpn-tx.ss
  ;; That transformer passes in an extra argument to find which
  ;; indicates what kind of function to return.

  ;; For state words, look for a genuine state word, or lift one from
  ;; the base dictionaries. For base words just return an unlifted
  ;; function. If symbol lookup fails, the parameterized function
  ;; 'not-found' is called with the appropriate failed paths.

  
  (define (make-state-find state base)
    (match-lambda*

     ((name 'state) (or
                     (lookup state name)
                     (state-lift
                      (lookup base name))
                     (not-found name state base)))

     ((name 'base)  (or
                     (lookup base name)
                     (not-found name base)))))
    

  ;; Using the function above, the 'state-stx' macro can be created
  ;; from 'state-rpn' defined in rpn-tx. Use the resulting macro as:

  ;; (state-stx lang: ((internal) ...)  ((external) ...))
  
  (rpn-compiler-stx  ns-state-stx   
                     ns-state-rpn
                     make-state-find)

  ;; For documentation see rpn.ss

  )