Can a function know what other function called it?

On 5/24/2009 10:23 AM, Romain Francois wrote:

Duncan Murdoch wrote:

On 23/05/2009 4:55 PM, Robert Gentleman wrote:

Kynn Jones wrote:

[snip]

  and you have a breakpoint in bar, you could not (easily) 
distinguish which of
the two calls to bar was active. There is no line counter or 
anything of that
sort available.

The evaluator doesn't pay any attention to srcref records, so this 
is still true, but it would be possible to keep the srcref on the 
stack as well as all the other info there.

Please

Here's a patch file that does this.  (Will it make it through to the 
mailing list?  We'll see.)  It's still in progress, so I'm not even 
ready to put it into R-devel, but you're welcome to try it out.

The basic idea is that it attaches srcref attributes to the values 
returned from sys.calls (which won't be displayed, but if you want to 
play with them you can) and to .Traceback (which traceback() will 
display).  debug() will also show them.

Not sure what bad side effects (e.g. on execution time) this has.

Duncan Murdoch

I've written code (and I think I sent it to you last year) that can 
do things like replacing the statement coming from a particular line 
of a file with whatever code you like; this could be used in writing 
a nice source-level debugger.

yes

Duncan Murdoch

 best wishes
   Robert