autocomplete - Custom tab completion in R function -

i writing function accepts inputs (in example "a" , "b"). other inputs function return error.

test <- function(x) {   allowedx <- c("a","b")   if(x %in% allowedx) print("good choice!")   else stop("wrong input!") } 

to users of function supply allowed values x (stored in allowedx) using tab completion feature in r , replace default file name completion typically applied after quote. pressing tab should give like:

test(x="<tab> b 

however, couldn't find solution far how map vector allowedx tab completion in r. can tell me how that?

thanks in advance!

you try following:

test <- function() {   allowedx <- c("a","b")   x = readline('please enter choice of parameters (either "a" or "b"): ')   if(x %in% allowedx) print("good choice!")   else stop("wrong input!") }