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tokenize.py
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# 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 string, re from codecs import BOM_UTF8, lookup from lib2to3.pgen2.token import * from . import token __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): 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. """ 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) 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 == 'def': if (stashed and stashed[0] == NAME and stashed[1] == 'async'): 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)