Adding metadata to R files

metadata.R

##
## From http://www.r-bloggers.com/adding-metadata-to-variables/
## 

# add a comment to a variable (NB -> comment(...) function is base R)
# example
xx <- 1:10
comment(xx) <- "one through ten"
attributes(xx) 
comment(xx) <- "another one"  # NB -> adding another comment overwrites the last one
attributes(xx) 


# Get current user
get_user <- function()
{
  env <- if(.Platform$OS.type == "windows") "USERNAME" else "USER"
  unname(Sys.getenv(env))    
} 

# Add some metadata to a variable before assignment (a wrapper for assign(...))
assign_with_metadata <- function(x, value, ..., pos = parent.frame(), inherits = FALSE)
{
  attr(value, "creator") <- get_user()
  attr(value, "time_created") <- Sys.time()
  more_attr <- list(...)
  attr_names <- names(more_attr)
  for(i in seq_along(more_attr))
  {
    attr(value, attr_names[i]) <- more_attr[[i]]
  }
  assign(x, value, pos = pos, inherits = inherits)
}
assign_with_metadata("x", 1:3, monkey = "chimp")  # example