[Rd] Am I missing something about debugging?

[Ross Boylan]

On Tue, 2007-01-02 at 17:24 -0500, Duncan Murdoch wrote:
> I don't think you're missing anything with the debug() function. It 
> needs updating.
Bummer!
> 
> I don't think there's any structural reason why you shouldn't be able to 
> do the things you're talking about in R, but they haven't been 
> implemented.
> 
That's good to know.  I was wondering if the lexical scoping was
complicating things.  At least the way I think of it, every call has two
sets of (potentially) nested environments: the lexical scopes of the
function definition and the dynamic scopes of the call.  But since the
dynamic scopes are available, using them seems possible.

> Mark Bravington put together a package (called debug) that does more 
> than debug() does, but I haven't used it much, and I don't know if it 
> does what you want.
> 
It looked to me as if it was some help, but no advance on the
investigating dynamic frames front.

> I recently added things to the R parser to keep track of connections 
> between R code and source files; that was partly meant as a first step 
> towards improving the debugging facilities.  I'd be happy to help anyone 
> who wants to do the hard work, but I don't think I'll be able to work on 
> it before next summer.  (If you do decide to work on it, please let me 
> know, just in case I do get a chance:  no point duplicating effort.)
I didn't even realize such a facility was needed, which shows how much I
know!  Working on the debugger is probably not in my job description,
unless I get really annoyed.

The smalltalk debugger is the standard by which I judge all others; it's
just amazing.  You can go up and down the stack, graphically examine
variables (and follow links), and change code in the middle of debugging
and then continue.

Ross