@leif can you explain this program to me? I don’t know why (eval 'vl-append pict-namespace) is raising an error. http://pasterack.org/pastes/92108

^ I mean, “why is ((eval 'vl-append pict-namespace) (blank 0 0)) raising an error”

@ben how did you constuct pict-namespace?

Because if it’s a different namespace, the runtime could be thinking they are two different struct types.

make-base-namespace … (namespace-require 'pict); it is a different namespace

@ben Ya, that is just because its a different namespace (and has nothing to do with pict.)

For example, if you add: (define-namespace-anchor anchor) (define pict-namespace2 (namespace-anchor->namespace anchor))

and use pict-namespace2 instead, it works out fine.

@ben @leif If the goal of pict-namespace is to isolate effects, then it’s better to use namespace-attach-module to attach pict to the new namespace. But maybe the just-pushed improvement to namespace-attach-module docs means that you’ already know that.

@mflatt Yup, exactly.

@ben and I (and Michael B.) figured that out, thanks though. :slightly_smiling_face:

well we should post the solution

@ben We did, by updating the docs. But in your case just adding a namespace-attach-module works.

Speaking of nothing….I just found out that if you have:

A) A slider,

B) A timer that updates the slider on a regular interval, and

C) Click and drag the slider,

then every time the timer goes off while you are still holding the slider gets treated as if it was a click, rather than being set via set-value!

Not sure if that’s a bug or an intended feature. Thoughts @mflatt?

solution: http://pasterack.org/pastes/63734

(“short” way to eval a string to a function from your favorite library)

Such as in this example: https://gist.github.com/LeifAndersen/ff07cb0ffd516b0333f2753db6e96c37

If you click and drag the slider around, the first callback will be what you want, but then you get a bunch of others that are not what you wanted.

Namely, you will get exactly how many as the amount the timer went off.

@leif that’s a bug

@mflatt Okay. I’ll try to hunt it down unless you beat me to it.

I haven’t investigated, but I think I know the problem: dragging puts the control in a “slider-value update means that a the slider was moved” mode, and calling set-value doesn’t temporarily suppress that mode while updating the value

@mflatt I agree that sounds like the bug. Its more a matter of digging in and finding it. :wink:

Mostly because the implementation for the functions is: (bounce c (get-value) (set-value v))

Which I am sure is great for code re-use, means I need to track down the actual get-value without the help of DrRacket’s arrows.

(which, to be clear, is absolutely fine with me. :slightly_smiling_face: )

I expected to see the problem in “gui-lib/mred/private/wx/cocoa/slider.rkt”, but I don’t see anything there to control when 'slider events are generated, so maybe my guess is wrong

Ya, about all I see is: (define/public (changed) (callback this (new control-event% [event-type 'slider] [time-stamp (current-milliseconds)])))

Ah, this looks promising: (define-objc-class RacketSlider NSSlider #:mixins (FocusResponder KeyMouseResponder CursorDisplayer) [wxb] (-a _void (changed: [_id sender]) (let ([wx (->wx wxb)]) (when wx (send wx update-message) (queue-window-event wx (lambda () (send wx changed))) (constrained-reply (send wx get-eventspace) (lambda () (let loop () (pre-event-sync #t) (when (yield/no-sync) (loop)))) (void))))))

And the queue-window-event would explain why you see all of the calls right after you let go.

I’m getting WARNING: bad 'scribblings info: '(("long//path/to/docs/main.scrbl")) - do scribble document modules for a collection have to only be one folder down from the collection? Do I have to make a second info.rkt module next to my scribble document with just scribblings defined?

nevermind, turned out to be a problem with the categories part of the scribblings info