CODEWITHSUNDEEP
r
John Horton
John Horton

Reputation: 4282

Is there an easy way to tell if an R script made use of any function in a loaded package?

For example, if ran the script.A: 

 library(ggplot2)
 a <- 12

and then script.B

library(ggplot2)
b <- runif(100)
qplot(b)

I'd be able to tell that script.A did not actually make use of ggplot2, whereas script.B did.

Upvotes: 8

Views: 373

Answers (2)

Ferdinand.kraft
Ferdinand.kraft

Reputation: 12819

Load the library normally and trace all functions in the package environment (and in the namespace). I'll use a small helper function to do this:

trap_funs <- function(env)
{
    f <- sapply(as.list(env, all.names=TRUE), is.function)
    for( n in names(f)[f] ) trace(n, bquote(stop(paste("Script called function", .(n)))), where=env)
}

Example:

library(data.table)
trap_funs(as.environment("package:data.table"))
trap_funs(asNamespace("data.table"))

This second statement is needed to ensure that calls such as data.table::xxx() also get trapped.

Example:

> as.data.table(mtcars)
Tracing as.data.table(mtcars) on entry 
Error in eval(expr, envir, enclos) : Script called function as.data.table

Note that the code was interrupted.

Upvotes: 5

G. Grothendieck
G. Grothendieck

Reputation: 269694

Try this:

1) First issue a library() call for each package that you do NOT want to test for. In this case there is only one package which is the one we wish to test for so we can skip this step.

2) Run the script with library dummied out:

library <- list
source("script.A")
rm(library) # restore

If you get no errors then the script does not depend on the package.

Upvotes: 0

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