;; meta:

(module meta mzscheme

  (require "ns.ss"
           "ns-base-stx.ss"
           "composite.ss"
           "base.ss"
           "rpn-eval.ss")

  (provide (all-defined))
           
  
  ;; --- partial evaluator / meta code ---

  ;; the assembler can contain delayed (partial) evaluations in symbolic
  ;; form. the canonical example of this is of course symbolic machine
  ;; constants, but the compiler is allowed to generate CAT expressions
  ;; as argument values for opcodes. these expressions should evaluate
  ;; to a number.

  ;; Meta language dictionary
  ;; (ns-new '(meta))

  (define-syntax meta-words
    (syntax-rules ()
      ((_ word ...)
       (compositions
        (meta) base:        ;; snarf from (base)
        (word word) ...))))

  (meta-words
   + - 2/ << >> <<< >>> and or xor * / pow)

  ;; Default meta language compiler and evaluator
  
  (ns-base-stx (meta:) ((meta)))


  (define (meta-eval exp)
    (apply values ;; so multiple values give an error
     ((rpn-compile exp 'meta:))))

  (rpn-modules "meta.ss")
  
  
)