def _tokenize(tex):
 start = 0
 try:
  try:
   pos = _stoppers.finditer(tex).next().span()[0]
  except AttributeError:
   pos = _stoppers.finditer(tex).__next__().span()[0]
 except StopIteration:
  (yield tex)
  return
 while 1:
  if (pos > start):
   (yield tex[start:pos])
   if ((tex[start] == '\\') and (not (tex[(pos - 1)].isdigit() and tex[(start + 1)].isalpha()))):
    while ((pos < len(tex)) and tex[pos].isspace()):
     pos += 1
  while ((pos < len(tex)) and (tex[pos] in _ignore)):
   pos += 1
  if (pos >= len(tex)):
   return
  start = pos
  if (tex[pos:(pos + 2)] in {'$$': None, '/~': None}):
   pos += 2
  elif tex[pos].isdigit():
   while ((pos < len(tex)) and tex[pos].isdigit()):
    pos += 1
  elif (tex[pos] == '-'):
   while ((pos < len(tex)) and (tex[pos] == '-')):
    pos += 1
  elif ((tex[pos] != '\\') or (pos == (len(tex) - 1))):
   pos += 1
  elif (not tex[(pos + 1)].isalpha()):
   pos += 2
  else:
   pos += 1
   while ((pos < len(tex)) and tex[pos].isalpha()):
    pos += 1
   if ((tex[start:pos] == '\\char') or (tex[start:pos] == '\\accent')):
    while ((pos < len(tex)) and tex[pos].isdigit()):
     pos += 1

def _tokenize ( tex ) : start = 0 try : try : pos = _stoppers . finditer ( tex ) . next ( ) . span ( ) [ 0 ] except AttributeError : pos = _stoppers . finditer ( tex ) . __next__ ( ) . span ( ) [ 0 ] except StopIteration : ( yield tex ) return while 1 : if ( pos > start ) : ( yield tex [ start : pos ] ) if ( ( tex [ start ] == '\\' ) and ( not ( tex [ ( pos - 1 ) ] . isdigit ( ) and tex [ ( start + 1 ) ] . isalpha ( ) ) ) ) : while ( ( pos < len ( tex ) ) and tex [ pos ] . isspace ( ) ) : pos += 1 while ( ( pos < len ( tex ) ) and ( tex [ pos ] in _ignore ) ) : pos += 1 if ( pos >= len ( tex ) ) : return start = pos if ( tex [ pos : ( pos + 2 ) ] in { '$$' : None , '/~' : None } ) : pos += 2 elif tex [ pos ] . isdigit ( ) : while ( ( pos < len ( tex ) ) and tex [ pos ] . isdigit ( ) ) : pos += 1 elif ( tex [ pos ] == '-' ) : while ( ( pos < len ( tex ) ) and ( tex [ pos ] == '-' ) ) : pos += 1 elif ( ( tex [ pos ] != '\\' ) or ( pos == ( len ( tex ) - 1 ) ) ) : pos += 1 elif ( not tex [ ( pos + 1 ) ] . isalpha ( ) ) : pos += 2 else : pos += 1 while ( ( pos < len ( tex ) ) and tex [ pos ] . isalpha ( ) ) : pos += 1 if ( ( tex [ start : pos ] == '\\char' ) or ( tex [ start : pos ] == '\\accent' ) ) : while ( ( pos < len ( tex ) ) and tex [ pos ] . isdigit ( ) ) : pos += 1
tokenize a strports string and yield each token .