[plt-scheme] paired braces in interaction mode?

On Sun, Mar 2, 2008 at 5:08 PM, Robby Findler <robby at cs.uchicago.edu> wrote:
>  It will presumably appear in the drscheme environment manual docs, but
>  I haven't yet ported them to the new documentation.
>
>  Still, it would help me if you had a more specific question.

I don't really understand how this feature is supposed to work or why
someone would want it, though the folks in the thread understand, so I
was hoping there would be a place in the manual that would explain
this feature.