[plt-scheme] Using FrTime

From: Gregory Cooper (greg at cs.brown.edu)
Date: Sun Oct 1 15:08:42 EDT 2006

Hi Jon,

As you've noticed, class.ss and fred.ss have to be explicitly required
before you can use the widget set.  However, once you've done so, they
should all work.  What errors do you get?  Do they happen on
"require", or when attempting to evaluate something?


On 10/1/06, Jon Rafkind <workmin at ccs.neu.edu> wrote:
> Im reading "Crossing State Lines: Adapting Object-Oriented Frameworks to
> Functional Reactive Languages" by Ignatoff, Cooper, and Krishnamurthi
> and would like to try out the first example but can't get it working in
> drscheme 352. I chose the FrTime language and typed this line into the
> definitions windows:
>    (define frame (new ft-frame% (label% "Timer") (width 200) (height 80)
> (visible #t)))
> Verbatim from the paper( except the paper used 'true' instead of #t ).
> This led to the error:
>    reference to undefined identifier: new
> So I did
>    (require (lib "class.ss"))
> But then got a different error:
>    reference to undefined identifier: ft-frame%
> Grepping through collects/frtime I found ft-frame% defined in
> frtime/demos/gui/fred.ss.
>   ~/tmp/src/drscheme-352/collects/frtime $ grep -r "ft-frame" *
>   demos/gui/demo/bindec.ss:(current-widget-parent (new ft-frame% (label
> "Binary<-->Decimal")))
>   demos/gui/demo/timer.ss:(current-widget-parent (new ft-frame% (width
> 400) (stretchable-width #t)))
>   demos/gui/fred.ss:  (define ft-frame%
>   demos/gui/simple.ss:          (set! fr (new ft-frame%)))
> If I require 'fred.ss' I get a bunch more errors which probably aren't
> worth going into. Am I missing something?
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