Extending lpeg's gsub example

[Marcus Mason <m4gicks@...>]

I'd like to extend this example so that I can specify the maximum number of replacements as in normal string.gsub

function gsub (s, patt, repl)
  patt = lpeg.P(patt)
  patt = lpeg.Cs((patt / repl + 1)^0)
  return lpeg.match(patt, s)
end

What would be the best way to achieve this?