Ah, well, that was more straightforward than I expected. I was lazy with my Saturday-night learning session and didn't push very hard to solve it on my own. Thank you for taking the time to help. I also appreciate that you caught those bugs and improved the code style. Thanks again.
On Saturday, May 25, 2019 at 8:19:23 PM UTC-7, Sorawee Porncharoenwase wrote: > > Just abstract the common part out? E.g., > > (define (update-text-field read-field write-field converter) > (define text (send read-field get-value)) > (cond > [(string=? text "") > (send read-field set-field-background (make-object color% 255 255 255 1)) > (send write-field set-value "")] > [(number? (string->number text)) > (send read-field set-field-background (make-object color% 255 255 255 1)) > (send write-field set-value (converter (string->number text)))] > [else > (send read-field set-field-background (make-object color% 255 0 0 1)) > (send write-field set-value "")])) > > (define (update-fahrenheit control event) > (update-text-field text-celsius text-fahrenheit convert-c)) > > (define (update-celsius control event) > (update-text-field text-fahrenheit text-celsius convert-f)) > > Note that your original code has a bug: you always use convert-c in both > directions. Obviously, in update-celsius you want to use convert-f. > > There’s also another subtle bug that I didn’t fix. Suppose you type an > invalid character (like “a”) to the left text field. This will make the > field become red. Now, switch to the right field and type “32”. The left > field will output “0” while being red, though it probably should now be > white. > > On Sat, May 25, 2019 at 7:57 PM Travis Hinkelman <[email protected] > <javascript:>> wrote: > >> Hi All, >> >> I'm working through the tasks in 7guis >> <https://eugenkiss.github.io/7guis/tasks> to learn about GUI programming >> in Racket. My code >> <https://gist.github.com/hinkelman/e35d4abf3203277c4428bcd6abad8183> for >> the temperature converter task works as expected but there is a lot of >> redundancy in my update-fahrenheit and update-celsius callback functions. I >> would appreciate feedback on how to make this code less redundant. >> >> Thanks, >> >> Travis >> >> -- >> You received this message because you are subscribed to the Google Groups >> "Racket Users" group. >> To unsubscribe from this group and stop receiving emails from it, send an >> email to [email protected] <javascript:>. >> To view this discussion on the web visit >> https://groups.google.com/d/msgid/racket-users/8f97260c-62be-4a6f-9459-244a88632ef9%40googlegroups.com >> >> <https://groups.google.com/d/msgid/racket-users/8f97260c-62be-4a6f-9459-244a88632ef9%40googlegroups.com?utm_medium=email&utm_source=footer> >> . >> For more options, visit https://groups.google.com/d/optout. >> > -- You received this message because you are subscribed to the Google Groups "Racket Users" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To view this discussion on the web visit https://groups.google.com/d/msgid/racket-users/f730a304-2edc-4257-a0ed-0c66f417ee19%40googlegroups.com. For more options, visit https://groups.google.com/d/optout.
