Let's say we are interested to get few parameters from fixed file name sceme we build a pattern:
pattern = ("OSD", Unicode/2, Number/2, "OBJECTS.xml")
where Unicode/2 = 2 characters of Unicode, Number/2 = 3 digit number

(Res, Matches) = match (pattern, u"OSDРУ99OBJECTS.xml")
Where Res = Boolean success/fail
if success
  [Lang, Clip] = Matches

in this case
  Lang = "PY"
  Clip = 99