detach("new_tmp")
attach(new.env(), name="new_tmp")
my_newenv <- as.environment("new_tmp")
source("C:/Users/tmp/tmp.R", local=my_newenv)
search()

xxx <- "this should not be overwritten"
y <- 10

my_newenv$printing_func(10) # the result should be 20!
print(my_newenv$xxx)

# <<< R script imported using source() function  >>>
# >>>
# >>>
xxx <- "this overwrote"
printing_func <- function(xx){
  xx + y
  print("it works")
}