simple gene extractor for access time testing

gistfile1.lua

rm = gt.region_mapping_new_seqfile_matchdescstart(arg[2])

cv = gt.custom_visitor_new()
function cv:visit_feature(fn)
  if fn:get_type() == "gene" then
    print(fn:extract_sequence("gene", false, rm):len())
  end
end

gs = gt.gff3_in_stream_new_sorted(arg[1])
cs = gt.custom_stream_new_sorted()
cs.instream = gs
function cs:next_tree()
  n = self.instream:next_tree()
  if n then
    n:accept(cv)
  end
  return n
end

local gn = cs:next_tree()
while (gn) do
  gn = cs:next_tree()
end