nim-regex find based split

split.nim

proc split*(s: string, sep: Regex): seq[string] =
  result = @[]
  var
    m = RegexMatch()
    ds = initDataSets(sep.states.len, true)
    first = 0
    last = 0
    n = 0
  while last <= s.len:
    first = last
    if findImpl(ds, s, sep, m, last) and
        m.boundaries.a <= m.boundaries.b:
      n = m.boundaries.b+1
      last = m.boundaries.a
    else:
      n = s.len+1
      last = s.len+1
    result.add(substr(s, first, last-1))
    if n > 0:
      last = n