Is there an R equivalent of the pythonic “if __name__ == ”__main__“: main()”?

Question

The objective is to have two simple ways to source some code, say func.R, containing a function. Calling R CMD BATCH func.R initializes the function and evaluat

Answer 1

It's a lot of work, but I finally got it (and posted at Rosetta Code).

This example exports a function called meaningOfLife. When the script is run by itself, it runs main. When imported by another R file, it does not run main.

#!/usr/bin/Rscript

meaningOfLife <- function() {
    42
}

main <- function(program, args) {
    cat("Main: The meaning of life is", meaningOfLife(), "\n")
}

getProgram <- function(args) {
    sub("--file=", "", args[grep("--file=", args)])
}

args <- commandArgs(trailingOnly = FALSE)
program <- getProgram(args)

if (length(program) > 0 && length(grep("scriptedmain", program)) > 0) {
    main(program, args)
    q("no")
}