;;;; condition-utils.inline.scm  -*- Scheme -*-
;;;; Kon Lovett, Jan '25

(define-type condition-predicate (* -> boolean : condition))
(define-type condition-property-accessor (condition -> *))

(define-syntax on1st
  (syntax-rules ()
    ((on1st ?typ ?e0 ...)
      (let ((+pred+ (the (or false ?typ) #f)))
        (lambda (x)
          (unless +pred+ (set! +pred+ (begin ?e0 ...)))
          (+pred+ x)) ) ) ) )

(define-syntax define-condition-predicate
  (syntax-rules ()
    ((define-condition-predicate ?n ?d0 ...)
      (define ?n
        (on1st condition-predicate
               (make-condition-predicate ?d0 ...))) ) ) )

(define-syntax define-condition-property-accessor
  (syntax-rules ()
    ((define-condition-property-accessor ?n ?d0 ...)
      (define ?n
        (on1st condition-property-accessor
               (make-condition-property-accessor ?d0 ...))) ) ) )