Running R function with arguments in 32 bit R, inside 64 bit R - r

Question

Suppose I want to run the function
test.function <- function(arg1){
print(arg1)
}
How can I run, lets say:
test.function("Hello world")
in 32 bit mode, using 64 bit R? I have managed running an entire script in 32 bit mode using
system(paste0(Sys.getenv("R_HOME"), "/bin/i386/Rscript.exe ",'"some_script.R"'))
But how can I change this, so that it can run a function with arguments, instead of an entire script?
EDIT
Following the answer by Roman Luštrik and running
system('Rscript test.script.R "hello"')
Gives me the following error:
Error in winDialog(type = "ok", message = message_text) :
winDialog() cannot be used non-interactively
call: -> check.for.updates.R -> winDialog
Running stopped
Warning message:
running command 'Rscript test.script.R "hello"' had status 1
(The error message was in my native language, so I had to translate a few words, so the text might differ slightly on other systems)

Answer 1

You can't run a specific function only, you will have to create a script. This does not stop you from creating a one-function only script, though.
If you create a script called test.script.R and put it somewhere where you can find it.
args <- commandArgs(trailingOnly = TRUE)
str(args)
test.function <- function(x) {
message("Your input:")
message(x)
}
invisible(sapply(args, test.function))
Open up a terminal window. You can use Windows' cmd.exe (press Windows key and type cmd.exe or Command Prompt or whatever you have in your perhaps localized version of the system). Navigate to where the script is located and run it using the below command.
$ Rscript test.script.R "hello" "hello" "won't you tell me your name" "i hate the doors"
chr [1:4] "hello" "hello" "won't you tell me your name" ...
Your input:
hello
Your input:
hello
Your input:
won't you tell me your name
Your input:
i hate the doors
Or, you could use system to do the same thing through R.
system('Rscript test.script.R "hello" "hello" "won't you tell me your name" "i hate the doors"')
Notice the way I use single and double quotes. Single quotes are on the outer side. This call also assumes the script is located in the workspace where R is currently looking. You can change that using setwd(), though.

Answer 2

I managed to find a solution myself, by modifying Roman Luštrik's solution.
Following his example we have the script called test_script.R:
args <- commandArgs(trailingOnly = TRUE)
test.function <- function(x) {
print(x)
}
args.run <- list(x = args)
mydata <- do.call(test.function, args = args.run)
save(mydata, file = "Data.Rda") # If you need the output to an R object
Then in another script that runs 64 bit R, we can run this function in 32 bit R by:
pathIn32BitRScript <- '"C:/Some path/test_script.R"'
system(paste0(Sys.getenv("R_HOME"), "/bin/i386/Rscript.exe", pathIn32BitRScript, " ", "Hello world") )
load("Data.Rda") # Loads the results into an object called mydata
invisible(file.remove("Data.Rda")) # Deletes the file we created
In this example we have x = "Hello World". In case you have spaces in your path you will need the double quotes as I have in this example.