Fixes for tokenize in Python 3.3

IPython/utils/_tokenize_py3.py

@@ -1,595 +1,595 b''
 """Patched version of standard library tokenize, to deal with various bugs.
 
 Based on Python 3.2 code.
 
 Patches:
 
 - Gareth Rees' patch for Python issue #12691 (untokenizing)
   - Except we don't encode the output of untokenize
   - Python 2 compatible syntax, so that it can be byte-compiled at installation
 - Newlines in comments and blank lines should be either NL or NEWLINE, depending
   on whether they are in a multi-line statement. Filed as Python issue #17061.
 - Export generate_tokens & TokenError
 - u and rb literals are allowed under Python 3.3 and above.
 
 ------------------------------------------------------------------------------
 Tokenization help for Python programs.
 
 tokenize(readline) is a generator that breaks a stream of bytes into
 Python tokens.  It decodes the bytes according to PEP-0263 for
 determining source file encoding.
 
 It accepts a readline-like method which is called repeatedly to get the
 next line of input (or b"" 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.  Additionally, all token lists start with an ENCODING token
 which tells you which encoding was used to decode the bytes stream.
 """
 from __future__ import absolute_import
 
 __author__ = 'Ka-Ping Yee <[e-mail]>'
 __credits__ = ('GvR, ESR, Tim Peters, Thomas Wouters, Fred Drake, '
                'Skip Montanaro, Raymond Hettinger, Trent Nelson, '
                'Michael Foord')
 import builtins
 import re
 import sys
 from token import *
 from codecs import lookup, BOM_UTF8
 import collections
 from io import TextIOWrapper
 cookie_re = re.compile("coding[:=]\s*([-\w.]+)")
 
 import token
 __all__ = token.__all__ + ["COMMENT", "tokenize", "detect_encoding",
                            "NL", "untokenize", "ENCODING", "TokenInfo"]
 del token
 
 __all__ += ["generate_tokens", "TokenError"]
 
 COMMENT = N_TOKENS
 tok_name[COMMENT] = 'COMMENT'
 NL = N_TOKENS + 1
 tok_name[NL] = 'NL'
 ENCODING = N_TOKENS + 2
 tok_name[ENCODING] = 'ENCODING'
 N_TOKENS += 3
 
 class TokenInfo(collections.namedtuple('TokenInfo', 'type string start end line')):
     def __repr__(self):
         annotated_type = '%d (%s)' % (self.type, tok_name[self.type])
         return ('TokenInfo(type=%s, string=%r, start=%r, end=%r, line=%r)' %
                 self._replace(type=annotated_type))
 
 def group(*choices): return '(' + '|'.join(choices) + ')'
 def any(*choices): return group(*choices) + '*'
 def maybe(*choices): return group(*choices) + '?'
 
 # Note: we use unicode matching for names ("\w") but ascii matching for
 # number literals.
 Whitespace = r'[ \f\t]*'
 Comment = r'#[^\r\n]*'
 Ignore = Whitespace + any(r'\\\r?\n' + Whitespace) + maybe(Comment)
 Name = r'\w+'
 
 Hexnumber = r'0[xX][0-9a-fA-F]+'
 Binnumber = r'0[bB][01]+'
 Octnumber = r'0[oO][0-7]+'
 Decnumber = r'(?:0+|[1-9][0-9]*)'
 Intnumber = group(Hexnumber, Binnumber, Octnumber, Decnumber)
 Exponent = r'[eE][-+]?[0-9]+'
 Pointfloat = group(r'[0-9]+\.[0-9]*', r'\.[0-9]+') + maybe(Exponent)
 Expfloat = r'[0-9]+' + Exponent
 Floatnumber = group(Pointfloat, Expfloat)
 Imagnumber = group(r'[0-9]+[jJ]', Floatnumber + r'[jJ]')
 Number = group(Imagnumber, Floatnumber, Intnumber)
 
 if sys.version_info.minor >= 3:
     StringPrefix = r'(?:[bB][rR]?|[rR][bB]?|[uU])?'
 else:
     StringPrefix = r'(?:[bB]?[rR]?)?'
 
 # Tail end of ' string.
 Single = r"[^'\\]*(?:\\.[^'\\]*)*'"
 # Tail end of " string.
 Double = r'[^"\\]*(?:\\.[^"\\]*)*"'
 # Tail end of ''' string.
 Single3 = r"[^'\\]*(?:(?:\\.|'(?!''))[^'\\]*)*'''"
 # Tail end of """ string.
 Double3 = r'[^"\\]*(?:(?:\\.|"(?!""))[^"\\]*)*"""'
 Triple = group(StringPrefix + "'''", StringPrefix + '"""')
 # Single-line ' or " string.
 String = group(StringPrefix + r"'[^\n'\\]*(?:\\.[^\n'\\]*)*'",
                StringPrefix + 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"~")
 
 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(StringPrefix + r"'[^\n'\\]*(?:\\.[^\n'\\]*)*" +
                 group("'", r'\\\r?\n'),
                 StringPrefix + r'"[^\n"\\]*(?:\\.[^\n"\\]*)*' +
                 group('"', r'\\\r?\n'))
 PseudoExtras = group(r'\\\r?\n', Comment, Triple)
 PseudoToken = Whitespace + group(PseudoExtras, Number, Funny, ContStr, Name)
 
 def _compile(expr):
     return re.compile(expr, re.UNICODE)
 
 tokenprog, pseudoprog, single3prog, double3prog = map(
     _compile, (Token, PseudoToken, Single3, Double3))
 endprogs = {"'": _compile(Single), '"': _compile(Double),
             "'''": single3prog, '"""': double3prog,
             "r'''": single3prog, 'r"""': double3prog,
             "b'''": single3prog, 'b"""': double3prog,
             "R'''": single3prog, 'R"""': double3prog,
             "B'''": single3prog, 'B"""': double3prog,
             "br'''": single3prog, 'br"""': double3prog,
             "bR'''": single3prog, 'bR"""': double3prog,
             "Br'''": single3prog, 'Br"""': double3prog,
             "BR'''": single3prog, 'BR"""': double3prog,
             'r': None, 'R': None, 'b': None, 'B': None}
 
 triple_quoted = {}
 for t in ("'''", '"""',
           "r'''", 'r"""', "R'''", 'R"""',
           "b'''", 'b"""', "B'''", 'B"""',
           "br'''", 'br"""', "Br'''", 'Br"""',
           "bR'''", 'bR"""', "BR'''", 'BR"""'):
     triple_quoted[t] = t
 single_quoted = {}
 for t in ("'", '"',
           "r'", 'r"', "R'", 'R"',
           "b'", 'b"', "B'", 'B"',
           "br'", 'br"', "Br'", 'Br"',
           "bR'", 'bR"', "BR'", 'BR"' ):
     single_quoted[t] = t
 
 if sys.version_info.minor >= 3:
     # Python 3.3
     for _prefix in ['rb', 'rB', 'Rb', 'RB', 'u', 'U']:
-        _t2 = prefix+'"""'
+        _t2 = _prefix+'"""'
         endprogs[_t2] = double3prog
         triple_quoted[_t2] = _t2
-        _t1 = prefix + "'''"
+        _t1 = _prefix + "'''"
         endprogs[_t1] = single3prog
         triple_quoted[_t1] = _t1
         single_quoted[_prefix+'"'] = _prefix+'"'
-        single_quoted[_prefix+"'"] + _prefix+"'"
+        single_quoted[_prefix+"'"] = _prefix+"'"
     del _prefix, _t2, _t1
     endprogs['u'] = None
     endprogs['U'] = None
 
 del _compile
 
 tabsize = 8
 
 class TokenError(Exception): pass
 
 class StopTokenizing(Exception): pass
 
 
 class Untokenizer:
 
     def __init__(self):
         self.tokens = []
         self.prev_row = 1
         self.prev_col = 0
         self.encoding = 'utf-8'
 
     def add_whitespace(self, tok_type, start):
         row, col = start
         assert row >= self.prev_row
         col_offset = col - self.prev_col
         if col_offset > 0:
             self.tokens.append(" " * col_offset)
         elif row > self.prev_row and tok_type not in (NEWLINE, NL, ENDMARKER):
             # Line was backslash-continued.
             self.tokens.append(" ")
 
     def untokenize(self, tokens):
         iterable = iter(tokens)
         for t in iterable:
             if len(t) == 2:
                 self.compat(t, iterable)
                 break
             tok_type, token, start, end = t[:4]
             if tok_type == ENCODING:
                 self.encoding = token
                 continue
             self.add_whitespace(tok_type, 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):
         # This import is here to avoid problems when the itertools
         # module is not built yet and tokenize is imported.
         from itertools import chain
         startline = False
         prevstring = False
         indents = []
         toks_append = self.tokens.append
 
         for tok in chain([token], iterable):
             toknum, tokval = tok[:2]
             if toknum == ENCODING:
                 self.encoding = tokval
                 continue
 
             if toknum in (NAME, NUMBER):
                 tokval += ' '
 
             # Insert a space between two consecutive strings
             if toknum == STRING:
                 if prevstring:
                     tokval = ' ' + tokval
                 prevstring = True
             else:
                 prevstring = False
 
             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)
 
 
 def untokenize(tokens):
     """
     Convert ``tokens`` (an iterable) back into Python source code. Return
     a bytes object, encoded using the encoding specified by the last
     ENCODING token in ``tokens``, or UTF-8 if no ENCODING token is found.
 
     The result is guaranteed to tokenize back to match the input so that
     the conversion is lossless and round-trips are assured.  The
     guarantee applies only to the token type and token string as the
     spacing between tokens (column positions) may change.
 
     :func:`untokenize` has two modes. If the input tokens are sequences
     of length 2 (``type``, ``string``) then spaces are added as necessary to
     preserve the round-trip property.
 
     If the input tokens are sequences of length 4 or more (``type``,
     ``string``, ``start``, ``end``), as returned by :func:`tokenize`, then
     spaces are added so that each token appears in the result at the
     position indicated by ``start`` and ``end``, if possible.
     """
     return Untokenizer().untokenize(tokens)
 
 
 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 argment, 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 b''
 
     def find_cookie(line):
         try:
             # Decode as UTF-8. Either the line is an encoding declaration,
             # in which case it should be pure ASCII, or it must be UTF-8
             # per default encoding.
             line_string = line.decode('utf-8')
         except UnicodeDecodeError:
             raise SyntaxError("invalid or missing encoding declaration")
 
         matches = cookie_re.findall(line_string)
         if not matches:
             return None
         encoding = _get_normal_name(matches[0])
         try:
             codec = lookup(encoding)
         except LookupError:
             # This behaviour mimics the Python interpreter
             raise SyntaxError("unknown encoding: " + encoding)
 
         if bom_found:
             if encoding != '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]
 
     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 open(filename):
     """Open a file in read only mode using the encoding detected by
     detect_encoding().
     """
     buffer = builtins.open(filename, 'rb')
     encoding, lines = detect_encoding(buffer.readline)
     buffer.seek(0)
     text = TextIOWrapper(buffer, encoding, line_buffering=True)
     text.mode = 'r'
     return text
 
 
 def tokenize(readline):
     """
     The tokenize() generator requires one argment, 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 bytes.  Alternately, readline
     can be a callable function terminating with StopIteration:
         readline = open(myfile, 'rb').__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
     logical line; continuation lines are included.
 
     The first token sequence will always be an ENCODING token
     which tells you which encoding was used to decode the bytes stream.
     """
     # This import is here to avoid problems when the itertools module is not
     # built yet and tokenize is imported.
     from itertools import chain, repeat
     encoding, consumed = detect_encoding(readline)
     rl_gen = iter(readline, b"")
     empty = repeat(b"")
     return _tokenize(chain(consumed, rl_gen, empty).__next__, encoding)
 
 
 def _tokenize(readline, encoding):
     lnum = parenlev = continued = 0
     numchars = '0123456789'
     contstr, needcont = '', 0
     contline = None
     indents = [0]
 
     if encoding is not None:
         if encoding == "utf-8-sig":
             # BOM will already have been stripped.
             encoding = "utf-8"
         yield TokenInfo(ENCODING, encoding, (0, 0), (0, 0), '')
     while True:             # loop over lines in stream
         try:
             line = readline()
         except StopIteration:
             line = b''
 
         if encoding is not None:
             line = line.decode(encoding)
         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 TokenInfo(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 TokenInfo(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 += 1
                 elif line[pos] == '\t':
                     column = (column//tabsize + 1)*tabsize
                 elif line[pos] == '\f':
                     column = 0
                 else:
                     break
                 pos += 1
             if pos == max:
                 break
 
             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 TokenInfo(COMMENT, comment_token,
                            (lnum, pos), (lnum, pos + len(comment_token)), line)
                     yield TokenInfo(NEWLINE, line[nl_pos:],
                            (lnum, nl_pos), (lnum, len(line)), line)
                 else:
                     yield TokenInfo(NEWLINE, line[pos:],
                            (lnum, pos), (lnum, len(line)), line)
                 continue
 
             if column > indents[-1]:           # count indents or dedents
                 indents.append(column)
                 yield TokenInfo(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]
                 yield TokenInfo(DEDENT, '', (lnum, pos), (lnum, pos), line)
 
         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 numchars or                  # ordinary number
                     (initial == '.' and token != '.' and token != '...')):
                     yield TokenInfo(NUMBER, token, spos, epos, line)
                 elif initial in '\r\n':
                     yield TokenInfo(NL if parenlev > 0 else NEWLINE,
                            token, spos, epos, line)
                 elif initial == '#':
                     assert not token.endswith("\n")
                     yield TokenInfo(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]
                         yield TokenInfo(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)
                         endprog = (endprogs[initial] or endprogs[token[1]] or
                                    endprogs[token[2]])
                         contstr, needcont = line[start:], 1
                         contline = line
                         break
                     else:                                  # ordinary string
                         yield TokenInfo(STRING, token, spos, epos, line)
                 elif initial.isidentifier():               # ordinary name
                     yield TokenInfo(NAME, token, spos, epos, line)
                 elif initial == '\\':                      # continued stmt
                     continued = 1
                 else:
                     if initial in '([{':
                         parenlev += 1
                     elif initial in ')]}':
                         parenlev -= 1
                     yield TokenInfo(OP, token, spos, epos, line)
             else:
                 yield TokenInfo(ERRORTOKEN, line[pos],
                            (lnum, pos), (lnum, pos+1), line)
                 pos += 1
 
     for indent in indents[1:]:                 # pop remaining indent levels
         yield TokenInfo(DEDENT, '', (lnum, 0), (lnum, 0), '')
     yield TokenInfo(ENDMARKER, '', (lnum, 0), (lnum, 0), '')
 
 
 # An undocumented, backwards compatible, API for all the places in the standard
 # library that expect to be able to use tokenize with strings
 def generate_tokens(readline):
     return _tokenize(readline, None)
 
 if __name__ == "__main__":
     # Quick sanity check
     s = b'''def parseline(self, line):
             """Parse the line into a command name and a string containing
             the arguments.  Returns a tuple containing (command, args, line).
             'command' and 'args' may be None if the line couldn't be parsed.
             """
             line = line.strip()
             if not line:
                 return None, None, line
             elif line[0] == '?':
                 line = 'help ' + line[1:]
             elif line[0] == '!':
                 if hasattr(self, 'do_shell'):
                     line = 'shell ' + line[1:]
                 else:
                     return None, None, line
             i, n = 0, len(line)
             while i < n and line[i] in self.identchars: i = i+1
             cmd, arg = line[:i], line[i:].strip()
             return cmd, arg, line
     '''
     for tok in tokenize(iter(s.splitlines()).__next__):
         print(tok)