| """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. |
| """ |
| |
| __author__ = 'Ka-Ping Yee <ping@lfw.org>' |
| __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 |
| |
| 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) |
| |
| # 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("[bB]?[rR]?'''", '[bB]?[rR]?"""') |
| # Single-line ' or " string. |
| String = group(r"[bB]?[rR]?'[^\n'\\]*(?:\\.[^\n'\\]*)*'", |
| r'[bB]?[rR]?"[^\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(r"[bB]?[rR]?'[^\n'\\]*(?:\\.[^\n'\\]*)*" + |
| group("'", r'\\\r?\n'), |
| r'[bB]?[rR]?"[^\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, |
| "br'''": single3prog, 'br"""': double3prog, |
| "R'''": single3prog, 'R"""': double3prog, |
| "B'''": single3prog, 'B"""': 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 |
| |
| 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 = None |
| |
| 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 |
| if tok_type == ENCODING: |
| self.encoding = token |
| continue |
| 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 |
| prevstring = False |
| for tok in 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(iterable): |
| """Transform tokens back into Python source code. |
| It returns a bytes object, encoded using the ENCODING |
| token, which is the first token sequence output by tokenize. |
| |
| 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 intput: |
| # Output bytes will tokenize the back to the input |
| t1 = [tok[:2] for tok in tokenize(f.readline)] |
| newcode = untokenize(t1) |
| readline = BytesIO(newcode).readline |
| t2 = [tok[:2] for tok in tokenize(readline)] |
| assert t1 == t2 |
| """ |
| ut = Untokenizer() |
| out = ut.untokenize(iterable) |
| if ut.encoding is not None: |
| out = out.encode(ut.encoding) |
| return out |
| |
| |
| 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: |
| line_string = line.decode('ascii') |
| except UnicodeDecodeError: |
| return None |
| |
| 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 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] |
| |
| 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(NL, line[nl_pos:], |
| (lnum, nl_pos), (lnum, len(line)), line) |
| else: |
| yield TokenInfo((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 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) |