Can define-values be used in internal definitions? For example: (define (test) (define-values (x y z) (values 1 2 3)) ) >> begin (possibly implicit): no expression after a sequence of internal definitions in: (begin (define-values (x y z) (values 1 2 3))) But it works in top level definition.

Yes, it can be used in internal definitions. The problem here is exactly what the error message says: the function must return value(s).

(define (test) (define-values (x y z) (values 1 2 3)) #f)

@sorawee I understand, thanks!

I like the mission control binding though… I’d really like the plain up-arrow to do this, as it does in racket cli

how are custom keybindings defined?

I can’t see the difference, what am I missing? https://docs.racket-lang.org/style/Textual_Matters.html

@ego check https://github.com/racket/racket/blob/master/pkgs/racket-doc/scribblings/style/textual.scrbl#L20\|https://github.com/racket/racket/blob/master/pkgs/racket-doc/scribblings/style/textual.scrbl#L20

Turns out Scribble fixes the bad example.

“Task failed successfully”

Or rather, check the snapshot doc: https://www.cs.utah.edu/plt/snapshots/current/doc/style/Textual_Matters.html?q=style#%28part._.Where_to_.Put_.Parentheses%29

It’s been fixed for a while, but the fix hasn’t made to the release doc (it should within a week?)

no worries, I guessed these were both the ‘good’ form :)

just want to say this slack is great, everyone is so helpful

https://docs.racket-lang.org/drracket/Keyboard_Shortcuts.html#%28part._defining-shortcuts%29\|https://docs.racket-lang.org/drracket/Keyboard_Shortcuts.html#%28part._defining-shortcuts%29

But I’m not sure that will be sufficient to cover changing the keybinding for arrow keys.

I found there is a count function can count element by comparing multiple lists. (count equal? list-a list-b) But it seems that I can’t do the same thing with sequence-count on multiple sequences. Also can’t do the same with stream-count.

Is there any suggestion?

(define xs (list 1 2 3)) (define ys (list 1 -2 3)) (sequence-count equal? (in-parallel xs ys))

(define xs (stream 1 2 3)) (define ys (stream 1 -2 3)) (stream-count equal? (sequence->stream (in-parallel xs ys)))

packaging question… I have seen a few packages which have a single main.rkt with (provides ...) from various private modules for the public interface of the package is main.rkt a privileged filename like info.rkt? or a package will expose the provided names from any files in the top-level dir? …or something else?

Yep. (require abc) will search abc/main.rkt

only main.rkt? so every package should have a main.rkt ?

I mean, technically you can ask people to always write (require abc/def), and this will look for abc/def.rkt, so strictly speaking, no.

But usually, it’s easier to write (require abc), so most library packages will have main.rkt

There’s also tool packages for DrRacket, and those will have tools.rkt instead of main.rkt

perfect, thanks