Records - like structs but less ugly and much less efficient

gistfile1.rkt

#lang racket

(require rackunit
         (for-syntax racket/syntax))

;Records - like structs but less ugly and much less efficient
(define-syntax (record stx)
  (syntax-case stx ()
    [(_ name slots ...)
     (with-syntax ([new-name (format-id #'name "new-~a" (syntax-e #'name))])
       (quasisyntax/loc stx
         (begin
           (define-struct/derived #,stx name (ht)
             #:property prop:procedure (lambda (self key)
                                         (match self
                                           [(struct name (ht))
                                            (hash-ref ht key)])))
           (define (new-name . values)
             (let ([ht (make-hash (map cons '(slots ...) values))])
               (name ht))))))]))

(record pos x y)
(define p (new-pos 1 2))
(check-equal? (p 'x) 1)
(pos? p)
(pos? 42)

See http://racket-lang.org/irc-logs/20120920.txt at around 19:37