Detecting `package_name::function_name()` with static code analysis - r

Question

I am trying to dive into the internals of static code analysis packages like codetools and CodeDepends, and my immediate goal is to understand how to detect function calls written as package_name::function_name() or package_name:::function_name(). I would have liked to just use findGlobals() from codetools, but this is not so simple.
Example function to analyze:
f <- function(n){
tmp <- digest::digest(n)
stats::rnorm(n)
}
Desired functionality:
analyze_function(f)
## [1] "digest::digest" "stats::rnorm"
Attempt with codetools:
library(codetools)
f = function(n) stats::rnorm(n)
findGlobals(f, merge = FALSE)
## $functions
## [1] "::"
##
## $variables
## character(0)
CodeDepends comes closer, but I am not sure I can always use the output to match functions to packages. I am looking for an automatic rule that connects rnorm() to stats and digest() to digest.
library(CodeDepends)
getInputs(body(f)
## An object of class "ScriptNodeInfo"
## Slot "files":
## character(0)
##
## Slot "strings":
## character(0)
##
## Slot "libraries":
## [1] "digest" "stats"
##
## Slot "inputs":
## [1] "n"
##
## Slot "outputs":
## [1] "tmp"
##
## Slot "updates":
## character(0)
##
## Slot "functions":
## { :: digest rnorm
## NA NA NA NA
##
## Slot "removes":
## character(0)
##
## Slot "nsevalVars":
## character(0)
##
## Slot "sideEffects":
## character(0)
##
## Slot "code":
## {
## tmp <- digest::digest(n)
## stats::rnorm(n)
## }
EDIT To be fair to CodeDepends, there is so much customizability and power for those who understand the internals. At the moment, I am just trying to wrap my head around collectors, handlers, walkers, etc. Apparently, it is possible to modify the standard :: collector to make special note of each namespaced call. For now, here is a naive attempt at something similar.
col <- inputCollector(`::` = function(e, collector, ...){
collector$call(paste0(e[[2]], "::", e[[3]]))
})
getInputs(quote(stats::rnorm(x)), collector = col)#functions
Browse[1]> getInputs(quote(stats::rnorm(x)), collector = col)#functions
stats::rnorm rnorm
NA NA

Answer 1

If you want to extract namespaced functions from a function, try something like this
find_ns_functions <- function(f, found=c()) {
if( is.function(f) ) {
# function, begin search on body
return(find_ns_functions(body(f), found))
} else if (is.call(f) && deparse(f[[1]]) %in% c("::", ":::")) {
found <- c(found, deparse(f))
} else if (is.recursive(f)) {
# compound object, iterate through sub-parts
v <- lapply(as.list(f), find_ns_functions, found)
found <- unique( c(found, unlist(v) ))
}
found
}
And we can test with
f <- function(n){
tmp <- digest::digest(n)
stats::rnorm(n)
}
find_ns_functions(f)
# [1] "digest::digest" "stats::rnorm"

Answer 2

Ok, so this was possible with CodeDepends previously, but a bit harder than it should have been. I've just committed version 0.5-4 to github, which now makes this really "easy". Essentially you just need to modify the default colonshandlers ("::" and/or ":::") as follows:
library(CodeDepends) # version >= 0.5-4
handler = function(e, collector, ..., iscall = FALSE) {
collector$library(asVarName(e[[2]]))
## :: or ::: name, remove if you don't want to count those as functions called
collector$call(asVarName(e[[1]]))
if(iscall)
collector$call(deparse((e))) #whole expr ie stats::norm
else
collector$vars(deparse((e)), input=TRUE) #whole expr ie stats::norm
}
getInputs(quote(stats::rnorm(x,y,z)), collector = inputCollector("::" = handler))
getInputs(quote(lapply( 1:10, stats::rnorm)), collector = inputCollector("::" = handler))
The first getInputs call above gives the result:
An object of class "ScriptNodeInfo"
Slot "files":
character(0)
Slot "strings":
character(0)
Slot "libraries":
[1] "stats"
Slot "inputs":
[1] "x" "y" "z"
Slot "outputs":
character(0)
Slot "updates":
character(0)
Slot "functions":
:: stats::rnorm
NA NA
Slot "removes":
character(0)
Slot "nsevalVars":
character(0)
Slot "sideEffects":
character(0)
Slot "code":
stats::rnorm(x, y, z)
As, I believe, desired.
One thing to note here is the iscall argument I've added to the colons handler. The default handler and applyhandlerfactory now have special logic so that when they invoke one of the colons handlers in a situation where it is a function being called, that is set to TRUE.
I haven't done extensive testing yet of what will happen when "stats::rnorm" appears in lieu of symbols, particularly in the inputs slot when calculating dependencies, but I'm hopeful that should all continue to work as well. If it doesn't let me know.
~G