[Rd] Recursively parsing srcrefs

[Hadley Wickham]

Hi all,

Is it possible to "recursively" parse srcrefs to match the recursive
structure of the underlying code?  I'm interested in this because it's
the final step in allowing functions to modify other functions while
preserving the original source. I've tried to make a bit of demo of
what I want to do below, and I think I may uncovered a bug in parse.

f <- function(x = T) {
  # This is a comment
  if (x)                  return(4)
  if (emergency_status()) return(T)
}

parsed_src <- parse(text = attr(f, "source"))
src_ref <- attr(parsed_src, "srcref")[[1]]

f_one <- parse(text = "{
  # This is a comment
  if (x)                  return(4)
  if (emergency_status()) return(T)
}")
attr(f_one, "srcref")[[1]]

f_inside <- parse(text = "
  # This is a comment
  if (x)                  return(4)
  if (emergency_status()) return(T)
")
f_inside # Displays incorrectly?
attr(f_inside, "srcref")[[1]]
# Should be:
#  # This is a comment
#  if (x)                  return(4)


Regards,

Hadley

-- 
Assistant Professor / Dobelman Family Junior Chair
Department of Statistics / Rice University
http://had.co.nz/