[plt-scheme] HtDP languages + emacs

knubee wrote:
> I mostly edit and debug Scheme programs from within emacs. I have 
> installed Quack which allows me to switch between different 
> implementations. However, I cannot figure out how to run plt programs 
> that rely on the "student languages."
> 
> In other words, Quack allows me to choose between mzscheme and mred, but 
> neither of these seem to support the following:
> 
>     (require (lib "draw.ss" "htdp"))
> 
>     (start 300 300)
> 
>      (draw-solid-disk (make-posn 100 50) 10 'red)  -> reference to
>     undefined identifier: make-posn
> 
> 
> Does this require me to start mzscheme (or mred) with a specific switch? 
> If so what?

Use the lang collection.

   (require (lib "htdp-advanced.ss" "lang"))
   (make-posn 1 2)

See collects/lang/doc.txt for more info.

-- 
Jens Axel Søgaard