gnucash/libgnucash/app-utils/simple-obj.scm
Geert Janssens 83d14e1c1c Restructure the src directory
It is split into
- /libgnucash (for the non-gui bits)
- /gnucash (for the gui)
- /common (misc source files used by both)
- /bindings (currently only holds python bindings)

This is the first step in restructuring the code. It will need much
more fine tuning later on.
2017-08-10 18:45:00 +02:00

81 lines
2.9 KiB
Scheme

;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;;; simple-obj.scm
;;; rudimentary "class" system for straight Scheme
;;;
;;; Bill Gribble <grib@billgribble.com> 20 Feb 2000
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;; This program is free software; you can redistribute it and/or
;; modify it under the terms of the GNU General Public License as
;; published by the Free Software Foundation; either version 2 of
;; the License, or (at your option) any later version.
;;
;; This program is distributed in the hope that it will be useful,
;; but WITHOUT ANY WARRANTY; without even the implied warranty of
;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
;; GNU General Public License for more details.
;;
;; You should have received a copy of the GNU General Public License
;; along with this program; if not, contact:
;;
;; Free Software Foundation Voice: +1-617-542-5942
;; 51 Franklin Street, Fifth Floor Fax: +1-617-542-2652
;; Boston, MA 02110-1301, USA gnu@gnu.org
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;; this is an extremely rudimentary object system. Each object is a
;; cons cell, where the car is a symbol with the class name and the
;; cdr is a vector of the slots.
;;
;; the "class object" is an instance of simple-class which just has
;; the name of the class and an alist of slot names to vector indices
;; as its slots.
;;
;; by convention, I name class objects (defined with make-simple-class)
;; <class-name> with class-smybol 'class-name. For example,
;;
;; (define <test-class> (make-simple-class 'test-class '(slot-1 slot-2)))
;; (define t (make-simple-obj <test-class>))
;; t ==> (test-class . #(#f #f))
;; the 'simple-class' class.
(define (make-simple-class class-symbol slot-names)
(make-record-type (symbol->string class-symbol) slot-names))
(define (simple-obj-getter class slot)
(record-accessor class slot))
(define (simple-obj-setter class slot)
(record-modifier class slot))
(define (simple-obj-print obj)
(write obj))
(define (simple-obj-to-list obj)
(let ((retval '()))
(for-each
(lambda (slot)
(let ((thunk (record-accessor (record-type-descriptor obj) slot)))
(set! retval (cons (thunk obj) retval))))
(record-type-fields (record-type-descriptor obj)))
(reverse retval)))
(define (simple-obj-from-list list type)
(let ((retval (make-simple-obj type)))
(for-each
(lambda (slot)
(let ((thunk (record-modifier type slot)))
(thunk retval (car list)))
(set! list (cdr list)))
(record-type-fields type))
retval))
(define (make-simple-obj class)
(let ((ctor (record-constructor class))
(field-defaults
(map (lambda (v) #f) (record-type-fields class))))
(apply ctor field-defaults)))