[plt-scheme] macro stepper enhancements

On Oct 21, 2009, at 4:59 PM, Jon Rafkind wrote:

> 1. I would like to hide a specific s-expression in the macro  
> stepper. If I right click on a something, like letrec-values, and  
> click 'hide' then all instances of letrec-values are hidden.

Do you mean "hide" as the macro stepper uses the term, or do you mean  
something more like "collapse s-expression"?

> 2. Going a step back takes a long time, I guess because the entire  
> computation from beginning to end is re-computed? Can all the steps  
> be cached along the way instead?

They are. The steps are only recomputed when you change the hiding  
policy. The time is being taken up by pretty-printing, coloring,  
clickback-attaching, etc. I'll check to see if any of the latter parts  
are happening outside of edit-sequences, but other than that I don't  
know of any way to speed it up.

Ryan