;;
;; util-tag.scm
;;
;; Implementation of data structure tags.
;;
;; ISC License
;;
;; Copyright 2023 Brmlab, z.s.
;; Dominik Pantůček <dominik.pantucek@trustica.cz>
;;
;; Permission to use, copy, modify, and/or distribute this software
;; for any purpose with or without fee is hereby granted, provided
;; that the above copyright notice and this permission notice appear
;; in all copies.
;; 
;; THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL
;; WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED
;; WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE
;; AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR
;; CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS
;; OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT,
;; NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
;; CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
;;

(declare (unit util-tag))

(import duck)

(module*
 util-tag
 #:doc ("A unifying module for compound data structures tagging.")
 (
  make-tag
  util-tag-make
  )

 (import scheme
	 (chicken string)
	 (chicken random))

 (define-syntax/doc make-tag
   ("* ```tag``` - unquoted symbol to base the tag on

Creates a unique and collision free symbol to identify compound data
structures based on lists and pairs.")
   (syntax-rules ()
     ((_ tag)
      (util-tag-make 'tag))))

 ;; Creates a tag symbol based on symbol
 (define (util-tag-make sym)
   (string->symbol
    (string-intersperse
     (cons
      (list->string
       (map
	char-upcase
	(string->list
	 (symbol->string sym))))
      (cons
       "-"
       (map (lambda (n)
	      (substring
	       (number->string
		(+ 256 (char->integer n))
		16)
	       1))
	    (string->list
	     (random-bytes
	      (make-string 8))))))
     "")))

 )