*****SPAM***** [plt-scheme] Conversion from vr. 103 to 202

From: John Clements (clements at brinckerhoff.org)
Date: Tue Nov 19 16:53:17 EST 2002

On Tuesday, November 19, 2002, at 04:25  PM, Michel Martin wrote:

>            I have a game that work in DrScheme103, but I would like to 
> run it under the 202 version. Is there something I can do to have the 
> same “Full Scheme Language” of 103 in 202? The “Pretty Big” language 
> doesn’t contain what I’m looking for… Or how can I transform those 
> next 2 points in the 202 version?
> 1.	It seems I have a problem using “override”… I receive: 
> “class*/names: override element is not an identifier or pair of 
> identifiers”. Here’s my code:

Check out chapter 4 of the mzlib manual, "Version 100-style classes."  
The short answer is that by requiring class100.ss, you can get the 
syntax of the old-style classes.

> 2. I get a similar problem with “ivar/proc”. It is not recognized in 
> (ivar/proc permission 'get-pen).

Classes now have methods, rather than fields containing closures, so 
what you're asking isn't _quite_ possible.  However, you can almost 
certainly replace your code with (lambda () (send permission get-pen)), 
or something similar.


john clements
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