[R] Clustering Functions used by Reverse-Dependencies

[Ivan Krylov]

В Sat, 24 Feb 2024 03:08:26 +0000
Leo Mada via R-help <r-help using r-project.org> пишет:

> Are there any tools to extract the function names called by
> reverse-dependencies?

For well-behaved packages that declare their dependencies correctly,
parsing the NAMESPACE for importFrom() and import() calls should give
you the explicit imports. (What if the package imports the whole
dependency? The safe assumption is that all functions are used, but it
comes with false positives. You could also walk the package code
looking for function names that may belong to the imported package, but
that may involve both false positives and false negatives.)

For the rest of the imports and uses of weak dependencies, you'll have
to walk the package code looking for the uses of the `::` operator. See
how R CMD check walks the package code in functions
tools:::.check_packages_used and codetools::checkUsage.

A less-well-behaved package can always load a namespace during runtime
and choose the functions to call depending on the phase of the moon or
weather on Jupiter. For these, like for the halting problem, there's no
general solution: the package could be written to say, "if Leonard's
function says I'm about to call foo::bar, I won't do it, otherwise I
will".

-- 
Best regards,
Ivan