On 1/2/2007 5:46 PM, Ross Boylan wrote: > 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.
I wouldn't call the dynamic scopes "nested", more like "chained". If a search fails in one of them, it never looks in the next one: only the lexical scope nesting does that. > >> 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. Everything except the "change code" part is pretty standard in a modern debugger; I'd hope an R debugger could do them. An interpreter like R could allow changes, but I'm not sure what the user interface would look like... Duncan Murdoch ______________________________________________ R-devel@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-devel
