I am still not very good at using R’s standard debugging tools, and I often find that neither the error nor the traceback tell me enough to figure out what is going on. I would like to change R’s default behavior on error to provide more information.
Specifically, I would always like the call, including the formals, the expression assigned to each formal (the default expression if the default is the expression assigned), and the value of each of the argument expressions as evaluated in place, all returned in a format that makes it unambiguous which expression has been matched to which formal and which values go with which expression. Since the values might be large or of unexpected or evanescent type, I’d like them to be returned in a format, such as a str(), that makes intelligent choices about truncation and correctly identifies promises and other object types that tend to evaluate themselves into something else before you see them.
And finally, I’d like all these things, together with the return value of each call, for every function on the call stack from the error back to (and including) some piece of code that I wrote. It seems to me that the natural structure would be a single R object, a list of lists, one list per call (perhaps tidied, broom-like, into a tibble with some list columns) that I could single-step through in the obvious way.
I apologize if I have described some standard R debugging tool that I just haven't learned how to use properly yet. Is this even possible? If it is, could it be implemented via R's available error handlers, or would it need some package-scale coding project?
I would most prefer a solution that changes the default error response to this, but if that is impracticable, I'd accept a solution that requires that I rerun a code chunk with a wrapper or something similar.