#lang racket
;; -----------------------------------------------------------------------------
;; library module
;; syntax def
;; definition = ... | (struct/kw name (field ...) options ...)
;; meaning: (struct name (field ...) options ...)
;; plus keyword-based constructor: name/kw
;; warning: the introduction of name/kw is non-hygienic
(define-syntax (struct/kw stx)
(syntax-case stx ()
[(_ name (field ...) . stuff)
(let* ([symbol-to-keyword-parameter
(lambda (s)
`(,(string->keyword (symbol->string (syntax-e s))) ,s))]
[args
(map symbol-to-keyword-parameter (syntax->list #'(field ...)))]
[name/kw
(datum->syntax stx
(string->symbol
(string-append (symbol->string (syntax-e #'name))
"/kw")))])
#`(begin
(struct name (field ...) . stuff)
(define (#,name/kw #,@(foldl append '[] args))
(name field ...))))]))
;; -----------------------------------------------------------------------------
;; usage example (could be separate module)
(struct/kw book (author title))
(define book1 (book/kw #:title "The Client" #:author "John Grisham" ))
(string=? (book-author book1) "John Grisham")
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