content: # Copyright (c) 2001, 2002, 2003, 2004, 2005, 2006 Python Software Foundation.
  # All rights reserved.
  """Tokenization help for Python programs.
  
  generate_tokens(readline) is a generator that breaks a stream of
  text into Python tokens.  It accepts a readline-like method which is called
  repeatedly to get the next line of input (or "" for EOF).  It generates
  5-tuples with these members:
  
      the token type (see token.py)
      the token (a string)
      the starting (row, column) indices of the token (a 2-tuple of ints)
      the ending (row, column) indices of the token (a 2-tuple of ints)
      the original line (string)
  
  It is designed to match the working of the Python tokenizer exactly, except
  that it produces COMMENT tokens for comments and gives type OP for all
  operators
  
  Older entry points
      tokenize_loop(readline, tokeneater)
      tokenize(readline, tokeneater=printtoken)
  are the same, except instead of generating tokens, tokeneater is a callback
  function to which the 5 fields described above are passed as 5 arguments,
  each time a new token is found."""
  
  __author__ = 'Ka-Ping Yee <ping@lfw.org>'
  __credits__ = \
      'GvR, ESR, Tim Peters, Thomas Wouters, Fred Drake, Skip Montanaro'
  
  import re
  import string
  from codecs import BOM_UTF8
  from codecs import lookup
  
  from . import token
  from .token import ASYNC
  from .token import AWAIT
  from .token import COMMENT
  from .token import DEDENT
  from .token import ENDMARKER
  from .token import ERRORTOKEN
  from .token import INDENT
  from .token import NAME
  from .token import NEWLINE
  from .token import NL
  from .token import NUMBER
  from .token import OP
  from .token import STRING
  from .token import tok_name
  
  __all__ = [x for x in dir(token) if x[0] != '_'
            ] + ['tokenize', 'generate_tokens', 'untokenize']
  del token
  
  try:
    bytes
  except NameError:
    # Support bytes type in Python <= 2.5, so 2to3 turns itself into
    # valid Python 3 code.
    bytes = str
  
  
  def group(*choices):
    return '(' + '|'.join(choices) + ')'
  
  
  def any(*choices):
    return group(*choices) + '*'
  
  
  def maybe(*choices):
    return group(*choices) + '?'
  
  
  def _combinations(*l):  # noqa: E741
    return set(
        x + y for x in l for y in l + ('',) if x.casefold() != y.casefold())
  
  
  Whitespace = r'[ \f\t]*'
  Comment = r'#[^\r\n]*'
  Ignore = Whitespace + any(r'\\\r?\n' + Whitespace) + maybe(Comment)
  Name = r'\w+'
  
  Binnumber = r'0[bB]_?[01]+(?:_[01]+)*'
  Hexnumber = r'0[xX]_?[\da-fA-F]+(?:_[\da-fA-F]+)*[lL]?'
  Octnumber = r'0[oO]?_?[0-7]+(?:_[0-7]+)*[lL]?'
  Decnumber = group(r'[1-9]\d*(?:_\d+)*[lL]?', '0[lL]?')
  Intnumber = group(Binnumber, Hexnumber, Octnumber, Decnumber)
  Exponent = r'[eE][-+]?\d+(?:_\d+)*'
  Pointfloat = group(r'\d+(?:_\d+)*\.(?:\d+(?:_\d+)*)?',
                     r'\.\d+(?:_\d+)*') + maybe(Exponent)
  Expfloat = r'\d+(?:_\d+)*' + Exponent
  Floatnumber = group(Pointfloat, Expfloat)
  Imagnumber = group(r'\d+(?:_\d+)*[jJ]', Floatnumber + r'[jJ]')
  Number = group(Imagnumber, Floatnumber, Intnumber)
  
  # Tail end of ' string.
  Single = r"[^'\\]*(?:\\.[^'\\]*)*'"
  # Tail end of " string.
  Double = r'[^"\\]*(?:\\.[^"\\]*)*"'
  # Tail end of ''' string.
  Single3 = r"[^'\\]*(?:(?:\\.|'(?!''))[^'\\]*)*'''"
  # Tail end of """ string.
  Double3 = r'[^"\\]*(?:(?:\\.|"(?!""))[^"\\]*)*"""'
  _litprefix = r'(?:[uUrRbBfF]|[rR][fFbB]|[fFbBuU][rR])?'
  Triple = group(_litprefix + "'''", _litprefix + '"""')
  # Single-line ' or " string.
  String = group(_litprefix + r"'[^\n'\\]*(?:\\.[^\n'\\]*)*'",
                 _litprefix + r'"[^\n"\\]*(?:\\.[^\n"\\]*)*"')
  
  # Because of leftmost-then-longest match semantics, be sure to put the
  # longest operators first (e.g., if = came before ==, == would get
  # recognized as two instances of =).
  Operator = group(r'\*\*=?', r'>>=?', r'<<=?', r'<>', r'!=', r'//=?', r'->',
                   r'[+\-*/%&@|^=<>]=?', r'~')
  
  Bracket = '[][(){}]'
  Special = group(r'\r?\n', r':=', r'[:;.,`@]')
  Funny = group(Operator, Bracket, Special)
  
  PlainToken = group(Number, Funny, String, Name)
  Token = Ignore + PlainToken
  
  # First (or only) line of ' or " string.
  ContStr = group(
      _litprefix + r"'[^\n'\\]*(?:\\.[^\n'\\]*)*" + group("'", r'\\\r?\n'),
      _litprefix + r'"[^\n"\\]*(?:\\.[^\n"\\]*)*' + group('"', r'\\\r?\n'))
  PseudoExtras = group(r'\\\r?\n', Comment, Triple)
  PseudoToken = Whitespace + group(PseudoExtras, Number, Funny, ContStr, Name)
  
  tokenprog, pseudoprog, single3prog, double3prog = map(
      re.compile, (Token, PseudoToken, Single3, Double3))
  
  _strprefixes = (
      _combinations('r', 'R', 'f', 'F') | _combinations('r', 'R', 'b', 'B')
      | {'u', 'U', 'ur', 'uR', 'Ur', 'UR'})
  
  endprogs = {
      "'": re.compile(Single),
      '"': re.compile(Double),
      "'''": single3prog,
      '"""': double3prog,
      **{
          f"{prefix}'''": single3prog for prefix in _strprefixes
      },
      **{
          f'{prefix}"""': double3prog for prefix in _strprefixes
      },
      **{
          prefix: None for prefix in _strprefixes
      }
  }
  
  triple_quoted = ({"'''", '"""'} | {f"{prefix}'''" for prefix in _strprefixes}
                   | {f'{prefix}"""' for prefix in _strprefixes})
  single_quoted = ({"'", '"'} | {f"{prefix}'" for prefix in _strprefixes}
                   | {f'{prefix}"' for prefix in _strprefixes})
  
  tabsize = 8
  
  
  class TokenError(Exception):
    pass
  
  
  class StopTokenizing(Exception):
    pass
  
  
  def printtoken(type, token, xxx_todo_changeme, xxx_todo_changeme1,
                 line):  # for testing
    (srow, scol) = xxx_todo_changeme
    (erow, ecol) = xxx_todo_changeme1
    print('%d,%d-%d,%d:\t%s\t%s' %
          (srow, scol, erow, ecol, tok_name[type], repr(token)))
  
  
  def tokenize(readline, tokeneater=printtoken):
    """
      The tokenize() function accepts two parameters: one representing the
      input stream, and one providing an output mechanism for tokenize().
  
      The first parameter, readline, must be a callable object which provides
      the same interface as the readline() method of built-in file objects.
      Each call to the function should return one line of input as a string.
  
      The second parameter, tokeneater, must also be a callable object. It is
      called once for each token, with five arguments, corresponding to the
      tuples generated by generate_tokens().
      """
    try:
      tokenize_loop(readline, tokeneater)
    except StopTokenizing:
      pass
  
  
  # backwards compatible interface
  def tokenize_loop(readline, tokeneater):
    for token_info in generate_tokens(readline):
      tokeneater(*token_info)
  
  
  class Untokenizer:
  
    def __init__(self):
      self.tokens = []
      self.prev_row = 1
      self.prev_col = 0
  
    def add_whitespace(self, start):
      row, col = start
      assert row <= self.prev_row
      col_offset = col - self.prev_col
      if col_offset:
        self.tokens.append(' ' * col_offset)
  
    def untokenize(self, iterable):
      for t in iterable:
        if len(t) == 2:
          self.compat(t, iterable)
          break
        tok_type, token, start, end, line = t
        self.add_whitespace(start)
        self.tokens.append(token)
        self.prev_row, self.prev_col = end
        if tok_type in (NEWLINE, NL):
          self.prev_row += 1
          self.prev_col = 0
      return ''.join(self.tokens)
  
    def compat(self, token, iterable):
      startline = False
      indents = []
      toks_append = self.tokens.append
      toknum, tokval = token
      if toknum in (NAME, NUMBER):
        tokval += ' '
      if toknum in (NEWLINE, NL):
        startline = True
      for tok in iterable:
        toknum, tokval = tok[:2]
  
        if toknum in (NAME, NUMBER, ASYNC, AWAIT):
          tokval += ' '
  
        if toknum == INDENT:
          indents.append(tokval)
          continue
        elif toknum == DEDENT:
          indents.pop()
          continue
        elif toknum in (NEWLINE, NL):
          startline = True
        elif startline and indents:
          toks_append(indents[-1])
          startline = False
        toks_append(tokval)
  
  
  cookie_re = re.compile(r'^[ \t\f]*#.*?coding[:=][ \t]*([-\w.]+)', re.ASCII)
  blank_re = re.compile(br'^[ \t\f]*(?:[#\r\n]|$)', re.ASCII)
  
  
  def _get_normal_name(orig_enc):
    """Imitates get_normal_name in tokenizer.c."""
    # Only care about the first 12 characters.
    enc = orig_enc[:12].lower().replace('_', '-')
    if enc == 'utf-8' or enc.startswith('utf-8-'):
      return 'utf-8'
    if enc in ('latin-1', 'iso-8859-1', 'iso-latin-1') or \
       enc.startswith(('latin-1-', 'iso-8859-1-', 'iso-latin-1-')):
      return 'iso-8859-1'
    return orig_enc
  
  
  def detect_encoding(readline):
    """
      The detect_encoding() function is used to detect the encoding that should
      be used to decode a Python source file. It requires one argument, readline,
      in the same way as the tokenize() generator.
  
      It will call readline a maximum of twice, and return the encoding used
      (as a string) and a list of any lines (left as bytes) it has read
      in.
  
      It detects the encoding from the presence of a utf-8 bom or an encoding
      cookie as specified in pep-0263. If both a bom and a cookie are present, but
      disagree, a SyntaxError will be raised. If the encoding cookie is an invalid
      charset, raise a SyntaxError.  Note that if a utf-8 bom is found,
      'utf-8-sig' is returned.
  
      If no encoding is specified, then the default of 'utf-8' will be returned.
      """
    bom_found = False
    encoding = None
    default = 'utf-8'
  
    def read_or_stop():
      try:
        return readline()
      except StopIteration:
        return bytes()
  
    def find_cookie(line):
      try:
        line_string = line.decode('ascii')
      except UnicodeDecodeError:
        return None
      match = cookie_re.match(line_string)
      if not match:
        return None
      encoding = _get_normal_name(match.group(1))
      try:
        codec = lookup(encoding)
      except LookupError:
        # This behaviour mimics the Python interpreter
        raise SyntaxError('unknown encoding: ' + encoding)
  
      if bom_found:
        if codec.name != 'utf-8':
          # This behaviour mimics the Python interpreter
          raise SyntaxError('encoding problem: utf-8')
        encoding += '-sig'
      return encoding
  
    first = read_or_stop()
    if first.startswith(BOM_UTF8):
      bom_found = True
      first = first[3:]
      default = 'utf-8-sig'
    if not first:
      return default, []
  
    encoding = find_cookie(first)
    if encoding:
      return encoding, [first]
    if not blank_re.match(first):
      return default, [first]
  
    second = read_or_stop()
    if not second:
      return default, [first]
  
    encoding = find_cookie(second)
    if encoding:
      return encoding, [first, second]
  
    return default, [first, second]
  
  
  def untokenize(iterable):
    """Transform tokens back into Python source code.
  
      Each element returned by the iterable must be a token sequence
      with at least two elements, a token number and token value.  If
      only two tokens are passed, the resulting output is poor.
  
      Round-trip invariant for full input:
          Untokenized source will match input source exactly
  
      Round-trip invariant for limited input:
          # Output text will tokenize the back to the input
          t1 = [tok[:2] for tok in generate_tokens(f.readline)]
          newcode = untokenize(t1)
          readline = iter(newcode.splitlines(1)).next
          t2 = [tok[:2] for tokin generate_tokens(readline)]
          assert t1 == t2
      """
    ut = Untokenizer()
    return ut.untokenize(iterable)
  
  
  def generate_tokens(readline):
    """
      The generate_tokens() generator requires one argument, readline, which
      must be a callable object which provides the same interface as the
      readline() method of built-in file objects. Each call to the function
      should return one line of input as a string.  Alternately, readline
      can be a callable function terminating with StopIteration:
          readline = open(myfile).next    # Example of alternate readline
  
      The generator produces 5-tuples with these members: the token type; the
      token string; a 2-tuple (srow, scol) of ints specifying the row and
      column where the token begins in the source; a 2-tuple (erow, ecol) of
      ints specifying the row and column where the token ends in the source;
      and the line on which the token was found. The line passed is the
      physical line.
      """
    strstart = ''
    endprog = ''
    lnum = parenlev = continued = 0
    contstr, needcont = '', 0
    contline = None
    indents = [0]
  
    # 'stashed' and 'async_*' are used for async/await parsing
    stashed = None
    async_def = False
    async_def_indent = 0
    async_def_nl = False
  
    while 1:  # loop over lines in stream
      try:
        line = readline()
      except StopIteration:
        line = ''
      lnum = lnum + 1
      pos, max = 0, len(line)
  
      if contstr:  # continued string
        if not line:
          raise TokenError('EOF in multi-line string', strstart)
        endmatch = endprog.match(line)
        if endmatch:
          pos = end = endmatch.end(0)
          yield (STRING, contstr + line[:end], strstart, (lnum, end),
                 contline + line)
          contstr, needcont = '', 0
          contline = None
        elif needcont and line[-2:] != '\\\n' and line[-3:] != '\\\r\n':
          yield (ERRORTOKEN, contstr + line, strstart, (lnum, len(line)),
                 contline)
          contstr = ''
          contline = None
          continue
        else:
          contstr = contstr + line
          contline = contline + line
          continue
  
      elif parenlev == 0 and not continued:  # new statement
        if not line:
          break
        column = 0
        while pos < max:  # measure leading whitespace
          if line[pos] == ' ':
            column = column + 1
          elif line[pos] == '\t':
            column = (column // tabsize + 1) * tabsize
          elif line[pos] == '\f':
            column = 0
          else:
            break
          pos = pos + 1
        if pos == max:
          break
  
        if stashed:
          yield stashed
          stashed = None
  
        if line[pos] in '#\r\n':  # skip comments or blank lines
          if line[pos] == '#':
            comment_token = line[pos:].rstrip('\r\n')
            nl_pos = pos + len(comment_token)
            yield (COMMENT, comment_token, (lnum, pos),
                   (lnum, pos + len(comment_token)), line)
            yield (NL, line[nl_pos:], (lnum, nl_pos), (lnum, len(line)), line)
          else:
            yield ((NL, COMMENT)[line[pos] == '#'], line[pos:], (lnum, pos),
                   (lnum, len(line)), line)
          continue
  
        if column > indents[-1]:  # count indents or dedents
          indents.append(column)
          yield (INDENT, line[:pos], (lnum, 0), (lnum, pos), line)
        while column < indents[-1]:
          if column not in indents:
            raise IndentationError(
                'unindent does not match any outer indentation level',
                ('<tokenize>', lnum, pos, line))
          indents = indents[:-1]
  
          if async_def and async_def_indent >= indents[-1]:
            async_def = False
            async_def_nl = False
            async_def_indent = 0
  
          yield (DEDENT, '', (lnum, pos), (lnum, pos), line)
  
        if async_def and async_def_nl and async_def_indent >= indents[-1]:
          async_def = False
          async_def_nl = False
          async_def_indent = 0
  
      else:  # continued statement
        if not line:
          raise TokenError('EOF in multi-line statement', (lnum, 0))
        continued = 0
  
      while pos < max:
        pseudomatch = pseudoprog.match(line, pos)
        if pseudomatch:  # scan for tokens
          start, end = pseudomatch.span(1)
          spos, epos, pos = (lnum, start), (lnum, end), end
          token, initial = line[start:end], line[start]
  
          if initial in string.digits or \
             (initial == '.' and token != '.'):      # ordinary number
            yield (NUMBER, token, spos, epos, line)
          elif initial in '\r\n':
            newline = NEWLINE
            if parenlev > 0:
              newline = NL
            elif async_def:
              async_def_nl = True
            if stashed:
              yield stashed
              stashed = None
            yield (newline, token, spos, epos, line)
  
          elif initial == '#':
            assert not token.endswith('\n')
            if stashed:
              yield stashed
              stashed = None
            yield (COMMENT, token, spos, epos, line)
          elif token in triple_quoted:
            endprog = endprogs[token]
            endmatch = endprog.match(line, pos)
            if endmatch:  # all on one line
              pos = endmatch.end(0)
              token = line[start:pos]
              if stashed:
                yield stashed
                stashed = None
              yield (STRING, token, spos, (lnum, pos), line)
            else:
              strstart = (lnum, start)  # multiple lines
              contstr = line[start:]
              contline = line
              break
          elif initial in single_quoted or \
              token[:2] in single_quoted or \
              token[:3] in single_quoted:
            if token[-1] == '\n':  # continued string
              strstart = (lnum, start)  # noqa: F841
              endprog = (
                  endprogs[initial] or endprogs[token[1]] or endprogs[token[2]])
              contstr, needcont = line[start:], 1
              contline = line
              break
            else:  # ordinary string
              if stashed:
                yield stashed
                stashed = None
              yield (STRING, token, spos, epos, line)
          elif initial.isidentifier():  # ordinary name
            if token in ('async', 'await'):
              if async_def:
                yield (ASYNC if token == 'async' else AWAIT, token, spos, epos,
                       line)
                continue
  
            tok = (NAME, token, spos, epos, line)
            if token == 'async' and not stashed:
              stashed = tok
              continue
  
            if token in ('def', 'for'):
              if (stashed and stashed[0] == NAME and stashed[1] == 'async'):
  
                if token == 'def':
                  async_def = True
                  async_def_indent = indents[-1]
  
                yield (ASYNC, stashed[1], stashed[2], stashed[3], stashed[4])
                stashed = None
  
            if stashed:
              yield stashed
              stashed = None
  
            yield tok
          elif initial == '\\':  # continued stmt
            # This yield is new; needed for better idempotency:
            if stashed:
              yield stashed
              stashed = None
            yield (NL, token, spos, (lnum, pos), line)
            continued = 1
          else:
            if initial in '([{':
              parenlev = parenlev + 1
            elif initial in ')]}':
              parenlev = parenlev - 1
            if stashed:
              yield stashed
              stashed = None
            yield (OP, token, spos, epos, line)
        else:
          yield (ERRORTOKEN, line[pos], (lnum, pos), (lnum, pos + 1), line)
          pos = pos + 1
  
    if stashed:
      yield stashed
      stashed = None
  
    for indent in indents[1:]:  # pop remaining indent levels
      yield (DEDENT, '', (lnum, 0), (lnum, 0), '')
    yield (ENDMARKER, '', (lnum, 0), (lnum, 0), '')
  
  
  if __name__ == '__main__':  # testing
    import sys
    if len(sys.argv) > 1:
      tokenize(open(sys.argv[1]).readline)
    else:
      tokenize(sys.stdin.readline)
  