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scm4e2.arc
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!Scm
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slib
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recobj
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1994-03-31
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;;; "recobj.scm" Records implemented as objects.
;;;From: whumeniu@datap.ca (Wade Humeniuk)
(require 'object)
(define record-type-name (make-generic-method))
(define record-accessor (make-generic-method))
(define record-modifier (make-generic-method))
(define record? (make-generic-predicate))
(define record-constructor (make-generic-method))
(define (make-record-type type-name field-names)
(define self (make-object))
(make-method! self record-type-name
(lambda (self)
type-name))
(make-method! self record-accessor
(lambda (self field-name)
(let ((index (comlist:position field-name field-names)))
(if (not index)
(slib:error "record-accessor: invalid field-name argument."
field-name))
(lambda (obj)
(record-accessor obj index)))))
(make-method! self record-modifier
(lambda (self field)
(let ((index (comlist:position field field-names)))
(if (not index)
(slib:error "record-accessor: invalid field-name argument."
field-name))
(lambda (obj newval)
(record-modifier obj index newval)))))
(make-method! self record? (lambda (self) #t))
(make-method! self record-constructor
(lambda (class . field-values)
(let ((values (apply vector field-values)))
(define self (make-object))
(make-method! self record-accessor
(lambda (self index)
(vector-ref values index)))
(make-method! self record-modifier
(lambda (self index newval)
(vector-set! values index newval)))
(make-method! self record-type-name
(lambda (self) (record-type-name class)))
self)))
self)
(provide 'record-object)
(provide 'record)