While a Smalltalk-style debugger would be pretty awesome, I suspect R's semantics would make restartable exceptions pretty difficult and R's current implementation would make getting the continuation-like object you'd need pretty difficult, at least across the range of platforms supported by R.
A solution, of course, would be to implement R's interpreter in Smalltalk as a domain-specific language. Vista Smalltalk apparently hosts a Lisp/Scheme interpreter and I know of at least one Lisp implementation for Squeak, which serve as pretty good starting points for an S-like language. :-) On 1/2/07, Ross Boylan <[EMAIL PROTECTED]> wrote: > On Tue, 2007-01-02 at 18:44 -0500, Duncan Murdoch wrote: > > On 1/2/2007 5:46 PM, Ross Boylan wrote: > .... > > > 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 > At least in MS Visual C++ a few years ago and gdb today, data tend not > to be presented in immediately digestible form. For a list or vector, > one gets the pointers and counts in the header, rather than the list > itself (and then if the objects are themselves complex (e.g., > std::string!), you have the problem of seeing bits rather than semantics > recursively). And I think neither put you inside an environment in > which you can do general operations in the language, such as invoking > methods on objects. The R browser already has that last feature. And I > see I left it out of my original list, which was focused more on stuff > not in the R debugger. Interactive function invocation immediately > allows friendlier presentation, since one can print or show any object > in the browser (print or show being among the methods one can invoke). > > I think ddd lets you graphically navigate your data. > > Visual C++ and maybe gdb/gcc are also moving to providing "edit and > continue" functionality in which you can change code and > recompile/relink on the fly. It's kind of brittle; for example if you > change the object layout or really anything in the ABI, you can edit > but you can't continue. > > In contrast, smalltalk is pretty good about even such tough cases as > redefining the slots (in R's lingo) of a class. For methods, if you are > in c, called from b, called from a, and you redefine b, the debugger > won't let you continue in b or c, but it will allow you to restart b and > continue from there. And if you stopped in b, you're free to redefine c > and then continue the execution, which will go into the new c code > (oops, a function named "c" written in smalltalk). > -- > Ross Boylan wk: (415) 514-8146 > 185 Berry St #5700 [EMAIL PROTECTED] > Dept of Epidemiology and Biostatistics fax: (415) 514-8150 > University of California, San Francisco > San Francisco, CA 94107-1739 hm: (415) 550-1062 > > ______________________________________________ > R-devel@r-project.org mailing list > https://stat.ethz.ch/mailman/listinfo/r-devel > -- Byron Ellis ([EMAIL PROTECTED]) "Oook" -- The Librarian ______________________________________________ R-devel@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-devel
