[plt-scheme] Evaluate text% contents

Hi all,

How can I read and evaluate the contents of a text% in the same manner  
as DrScheme's Definitions window?

Context: In the snip implementation I'm working on, I ultimately want  
to be able to use this snip as a piece of a program in DrScheme.   
Right now I'm just creating a scheme:text% (as in my recent post); is  
there a more appropriate class?

Possibly a better question: what approach was used for testing the  
snip classes that are now integrated with DrScheme (e.g., matrix-snip,  
number-snip, cache-image-snip), or what approach would now be best?

Thanks,
jmj