[plt-scheme] indenting algorithms for Scheme code?

At Thu, 18 Dec 2003 15:54:47 -0500, Ken Anderson wrote:
> I'd like to have a Java window (outside of PLT-Scheme) that can indent Scheme 
> expressions as they are entered.  I've looked at how Emacs does it, but it 
> winds up calling a built in function that keeps track of a 15 element state 
> vector.  I keep thinking its like reading what you've typed backwards until 
> you find a landmark like a "(let ".   Is there a programming pearl hear i 
> should know about?

I don't think so. In the past few weeks, we ditched a hueristic
backward paren-balancer in DrScheme, and switched to accurately lexing
code (forward) to match parens. Our heuristic backward balancer worked
ok for many years, but it was often annoying.

Matthew