Outputting a vector with repeated values

To keep my script records clean, I'd like to output vector inputs with rep() instead of repeated values in chain. Please see my example below, using dput():

v<-c(rep(1,2), rep(2,4), rep(NA,5))
dput(v)
>c(1, 1, 2, 2, 2, 2, NA, NA, NA, NA, NA)
unknown_function(v)
>c(rep(1,2), rep(2,4), rep(NA,5))

Surely trivial, but I cannot find any simple solution. Suggestions for unknown_function(), please?