[R] Input buffer overflow

[Gabor Grothendieck]

In gsubfn I replace matches with strings that represent calls to a function
and then perform paste(eval(parse(text= ...)), collapse = "") on the result.
One user of gsubfn is using it with very long strings (over 20,000 characters)
and the parse is giving an input buffer overflow.  Here is an
artificial example:

   > s <- paste(rep("X", 25000), collapse = "")
   > out <- parse(text = shQuote(s))
   Error in parse(text = shQuote(s)) : input buffer overflow

Is there a way to increase the limit?