pkc-mode.el

(require 'generic-x)

;; pkc mode keywords
(setq pkc-keywords-list '("compute" "count" "dedupe" "embed" "file" "frequency" "function"
                          "join" "keep" "macro" "minus" "print" "project" "result" "select" "union" "use"))

(require 'mmm-auto)
(setq mmm-global-mode 'maybe)

(mmm-add-classes
 '((embedded-c++
    :submode c++-mode
    :face mmm-default-submode-face
    :front "{{{"
    :front-offset -1
    :back "}}}"
    :back-offset 1)))

(define-generic-mode
  'pkc-mode                                  ;; name of the mode to create
  '("//" ("/*" . "*/"))                       ;; comments start with
  pkc-keywords-list                          ;; some keywords

  '(("^\\s-*macro\\s-+\\([A-Za-z0-9_]+\\)"
     (1 font-lock-function-name-face))
    ("\\$\\([A-Za-z0-9_]+\\)"
     (0 font-lock-variable-name-face)))
  
  '("\\.pkc$")                             ;; files for which to activate this mode
    
  ;; other functions to call
  '((lambda ()
      (require 'mmm-vars)
      (mmm-add-mode-ext-class 'pkc-mode nil 'embedded-c++)
      (message "pkc-mode[mmm] is on")))

  "A mode for pkc script files"                  ;; doc string for this mode
  )

test.pkc

use "some-file.pkc"

embed {{{
    // C++ code

    int incr(int x)
    {
        return x + 1;
    }
}}}

// some pkc code