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#| Copyright (C) 2025 Peter McGoron
 |
 | Permission is hereby granted, free of charge, to any person obtaining a
 | copy of this software and associated documentation files (the
 | "Software"), to deal in the Software without restriction, including
 | without limitation the rights to use, copy, modify, merge, publish,
 | distribute, sublicense, and/or sell copies of the Software, and to
 | permit persons to whom the Software is furnished to do so, subject to
 | the following conditions:
 |
 | The above copyright notice and this permission notice (including the
 | next paragraph) shall be included in all copies or substantial portions
 | of the Software.
 |
 | THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
 | OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
 | MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
 | IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
 | CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
 | TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
 | SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 |#

(define-library (srfi 259)
  (import (scheme base) (scheme write)
          integer-map
          (chicken base)
          (chicken foreign)
          (chicken condition)
          (chicken fixnum))
  (export define-procedure-tag)
  (include "lowlevel.scm")
  (begin
    (define-syntax define-procedure-tag
      (syntax-rules ()
        ((define-procedure-tag constructor predicate? accessor)
         ;; Hygiene is broken here on CHICKEN, because `id` is not renamed
         ;; here. It needs to be lexical, not global.
         (begin
           (define constructor #f)
           (define predicate? #f)
           (define accessor #f)
           (let ((id (unique-id)))
             (set! constructor
                   (lambda (tag proc)
                     (set-tagged-mapping proc id tag)))
             (set! predicate?
                   (lambda (proc)
                     (cond
                       ((not (procedure? proc)) #f)
                       ((get-mapping proc) => (cut fxmapping-contains? <> id))
                       (else #f))))
             (set! accessor
                   (lambda (proc)
                     (let ((map (get-mapping proc))
                           (raise-error (lambda ()
                                          (raise
                                           (make-property-condition
                                            '(srfi-259 assertion-violation)
                                            'message
                                            "procedure does not contain id"
                                            'arguments
                                            (list proc id))))))
                       (if map
                           (fxmapping-ref map id raise-error)
                           (raise-error))))))))))))