(module (engine guards) ()
(import scheme
	(chicken base)
	(chicken module)
	(srfi 99))

;; Utility function for guarding parameter values
(export guarded-parameter)
(define (guarded-parameter default predicate)
  (make-parameter default (lambda (val)
			    (if (predicate val)
				val
				default))))

;; Guarded record functions
(export guarded-mutator)
;; Shorthand for defining a guarded mutator for a record field
(define (guarded-mutator record-type field predicate)
  (lambda (rec val)
    (assert (record-type rec))
    (assert (predicate val))
    ((rtd-mutator (record-rtd rec) field) rec val)))

;; TODO: define a similar function here for record constructor

;; TODO: define a similar function here for binary operations on records
)