#lang racket/base (require racket/gui/base racket/class racket/match) ;;; Laurent Orseau <laurent orseau gmail com> -- 2012-04-21 ;; Sample identity function: ;; string? -> (or/c string? #f) (provide item-callback) (define (item-callback str) (define c-old (match (read (open-input-string str)) [(list 'make-object 'color% r g b) (make-object color% r g b)] [else #f])) (let ([c (get-color-from-user #f #f c-old)]) (and c (format "(make-object color% ~a ~a ~a)" (send c red) (send c green) (send c blue))))) ;; See the manual in the Script/Help menu for more information. ; (make-object color% 148 37 37)