关于球拍：Chez计划记录-功能复制/更新？

Chez Scheme Record - Functional Copy/Update?

我已经在Chez Scheme文档中搜索了此问题的答案，但似乎找不到它：

Chez的记录是否具有功能性的副本/更新-类似Racket的结构？

谢谢。

支持功能更新的记录在SRFI 57中指定。实现由其原始作者Andr ??？ van Tonder，作为可移植的R7RS库。可以在Chez中容纳R6RS的简单package器(包含R6RS)在野外使用，但是我将推荐一个综合系统，该系统可以出色地"大力摇晃代码直到其表现正常"，即Akku.scm。

。

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我最近编写了一个名为define-immutable-record的宏，该宏生成一个不可变的记录类型，并带有如下命名的过程：record-with-field，该过程返回记录的更新副本。它是：

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;; Synthesises a symbol from strings and syntax objects
(meta define (synth-symbol . parts)
(define (part->string x)
(if (string? x) x (symbol->string (syntax->datum x))))
(string->symbol (apply string-append (map arg->string parts))))

;; Synthesises an identifier for use in an unhygenic macro
(meta define (gen-id template-id . parts)
(datum->syntax template-id (apply synth-symbol parts)))

;; Defines a record with all fields being immutable. Also defines
;; functions of the form `record-with-field`, e.g:
;;
;; (define-immutable-record point (x 0) (y 1))
;; (make-point) => (point (x 0) (y 1))
;; (make-point 3) => (point (x 3) (y 1))
;; (point-with-x (make-point 3 4) 99) => (point (x 99) (y 4))
(define-syntax define-immutable-record
(lambda (x)

(define (gen-ids k record-name conj-str fields)
(dat->syn k (map (lambda (f) (synth-symbol record-name conj-str f))
(syn->dat fields))))

(syntax-case x ()
((k record-name field ...)
(with-syntax ((make-fn (gen-id #'k"make-" #'record-name))
((with-fn ...) (gen-ids #'k #'record-name"-with-" #'(field ...)))
((get-fn ...) (gen-ids #'k #'record-name"-" #'(field ...))))
#'(begin
(define-record-type record-name
(fields (immutable field) ...))

(define (with-fn record new-value)
(let ([field (get-fn record)] ...)
(let ([field new-value])
(make-fn field ...)))) ...))))))