it helps a lot. Thx, have a nice day -:) 在2020年12月6日星期日 UTC+8 下午3:47:31<gneuner2> 写道：
> On Sat, 5 Dec 2020 19:26:30 -0800 (PST), Yi Chen > <[email protected]> wrote: > > > #lang slideshow > > (define cat <some_picture>) > > (image-width (cat)) > > There is no function "image-width" in slideshow. > > see: https://docs.racket-lang.org/search/index.html?q=image-width > To use "image-width" you must require one of these library modules: > - htdp/image > - 2htdp/image > - quadwriter > > > Additionally your syntax is wrong: it should be "(image-width cat)". > With the parentheses, "(cat)" is a call of a function named "cat" - > however "cat" is not a function but simply an image. > > Hope this helps, > George > > -- 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/137bcc44-3609-4cb8-ad18-06e9339cea39n%40googlegroups.com.
