[plt-scheme] PLT's debugger philosophy

On Feb 12, 2008, at 2:23 PM, Gregory Cooper wrote:

> If you're asking about the Debug button, I don't think there's any
> particular "philosophy" behind it.  It's just something I've hacked up
> and various other people (mainly Matthew) have helped to maintain.
>
> Actually, I don't think the Debug button works so differently from
> what you've described in MIT Scheme, except that you need to enable it
> explicitly when you start the program.  (This is because the
> breakpoint and introspection capabilities require source annotation,
> which incurs some overhead.)  The other differences are primarily in
> the user interface.

Do you mean that the debugger is just missing an input field where  
the user would be able to type an expression for the runtime to  
evaluate in the context of the environment where the debugger has  
paused?

That struck me as a feature that Grant listed (when he said "at which  
point you've got access to that stack frame at the location of the  
error at which point you can evaluate expressions") that I do not  
immediately see when reaching a breakpoint I set after using the  
Debug button.

But I am not a PLT Scheme expert, so perhaps there is some way to get  
this effect via the Debug button that I am not seeing.

-Felix

p.s. Just so I do not step on anyone's toes: I am not complaining  
about anything; PLT Scheme is great; "I'm not worthy"; etc.