On 13-01-14 4:08 PM, Ross Boylan wrote:
Is there an easy way to identify all the functions called as a result of
invoking a function? Getting the calling hierarchy too would be nice,
but is definitely not essential.
I think codetools could do this reasonably well with the walkCode
function, but I've never done it so I don't have sample code, and
walkCode is mostly an internal function.
The other way to do it is to run Rprof. It's only a sampling profiler,
so you don't get complete coverage, but it sees what really happens at
run-time. The proftools package can generate a call tree. (In R 3.0.0
you'll probably be able to extend this coverage analysis to the
statement level, but it's not there yet.)
I'm trying to understand someone else's package, which is in a namespace
and has some S3 functions. I could probably live without tracing the S3
functions. All the functions I want to trace are in R. The code passes
functions around as arguments, so that the function being called is not
always obvious from inspection of the source immediately around the
call.
Right, that makes it hard. I don't know if walkCode could figure that
stuff out, and the current Rprof won't know the original name if you do
something like
f <- mean
f(3)
The new stuff should be able to help in cases where the called function
is written in R and is slow enough to be caught by the profiler. If you
want to try it out and can compile R-devel for yourself, write to me and
I'll send you a patch offline.
I can imagine a solution that went something like this:
1. identify all functions by searching the sources for xxxx <- function(
(probably only at the left margin, to avoid attempting to trace
functions defined inside of functions).
2. Write a function that wraps another function to record the fact that
it has been called.
3. Somehow replace all functions with their wrapped equivalents.
4. make the top level call.
5. inspect the data constructed by the wrapper.
The code is recursive and iterative; manual stepping does not seem
feasible. The package includes a lot of earlier versions of the code,
and so I suspect that a lot of the code is not active.
Duncan Murdoch
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