Editing: tokenize.py
"""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, Raymond Hettinger') from itertools import chain import string, re from token import * import token __all__ = [x for x in dir(token) if not x.startswith("_")] __all__ += ["COMMENT", "tokenize", "generate_tokens", "NL", "untokenize"] del x del token COMMENT = N_TOKENS tok_name[COMMENT] = 'COMMENT' NL = N_TOKENS + 1 tok_name[NL] = 'NL' N_TOKENS += 2 def group(*choices): return '(' + '|'.join(choices) + ')' def any(*choices): return group(*choices) + '*' def maybe(*choices): return group(*choices) + '?' Whitespace = r'[ \f\t]*' Comment = r'#[^\r\n]*' Ignore = Whitespace + any(r'\\\r?\n' + Whitespace) + maybe(Comment) Name = r'[a-zA-Z_]\w*' Hexnumber = r'0[xX][\da-fA-F]+[lL]?' Octnumber = r'(0[oO][0-7]+)|(0[0-7]*)[lL]?' Binnumber = r'0[bB][01]+[lL]?' Decnumber = r'[1-9]\d*[lL]?' Intnumber = group(Hexnumber, Binnumber, Octnumber, Decnumber) Exponent = r'[eE][-+]?\d+' Pointfloat = group(r'\d+\.\d*', r'\.\d+') + maybe(Exponent) Expfloat = r'\d+' + Exponent Floatnumber = group(Pointfloat, Expfloat) Imagnumber = group(r'\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'[^"\\]*(?:(?:\\.|"(?!""))[^"\\]*)*"""' Triple = group("[uUbB]?[rR]?'''", '[uUbB]?[rR]?"""') # Single-line ' or " string. String = group(r"[uUbB]?[rR]?'[^\n'\\]*(?:\\.[^\n'\\]*)*'", r'[uUbB]?[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'[:;.,`@]') Funny = group(Operator, Bracket, Special) PlainToken = group(Number, Funny, String, Name) Token = Ignore + PlainToken # First (or only) line of ' or " string. ContStr = group(r"[uUbB]?[rR]?'[^\n'\\]*(?:\\.[^\n'\\]*)*" + group("'", r'\\\r?\n'), r'[uUbB]?[rR]?"[^\n"\\]*(?:\\.[^\n"\\]*)*' + group('"', r'\\\r?\n')) PseudoExtras = group(r'\\\r?\n|\Z', Comment, Triple) PseudoToken = Whitespace + group(PseudoExtras, Number, Funny, ContStr, Name) tokenprog, pseudoprog, single3prog, double3prog = map( re.compile, (Token, PseudoToken, Single3, Double3)) endprogs = {"'": re.compile(Single), '"': re.compile(Double), "'''": single3prog, '"""': double3prog, "r'''": single3prog, 'r"""': double3prog, "u'''": single3prog, 'u"""': double3prog, "ur'''": single3prog, 'ur"""': double3prog, "R'''": single3prog, 'R"""': double3prog, "U'''": single3prog, 'U"""': double3prog, "uR'''": single3prog, 'uR"""': double3prog, "Ur'''": single3prog, 'Ur"""': double3prog, "UR'''": single3prog, 'UR"""': double3prog, "b'''": single3prog, 'b"""': double3prog, "br'''": single3prog, 'br"""': double3prog, "B'''": single3prog, 'B"""': double3prog, "bR'''": single3prog, 'bR"""': double3prog, "Br'''": single3prog, 'Br"""': double3prog, "BR'''": single3prog, 'BR"""': double3prog, 'r': None, 'R': None, 'u': None, 'U': None, 'b': None, 'B': None} triple_quoted = {} for t in ("'''", '"""', "r'''", 'r"""', "R'''", 'R"""', "u'''", 'u"""', "U'''", 'U"""', "ur'''", 'ur"""', "Ur'''", 'Ur"""', "uR'''", 'uR"""', "UR'''", 'UR"""', "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"', "u'", 'u"', "U'", 'U"', "ur'", 'ur"', "Ur'", 'Ur"', "uR'", 'uR"', "UR'", 'UR"', "b'", 'b"', "B'", 'B"', "br'", 'br"', "Br'", 'Br"', "bR'", 'bR"', "BR'", 'BR"' ): single_quoted[t] = t tabsize = 8 class TokenError(Exception): pass class StopTokenizing(Exception): pass def printtoken(type, token, srow_scol, erow_ecol, line): # for testing srow, scol = srow_scol erow, ecol = erow_ecol 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 if row < self.prev_row or row == self.prev_row and col < self.prev_col: raise ValueError("start ({},{}) precedes previous end ({},{})" .format(row, col, self.prev_row, self.prev_col)) row_offset = row - self.prev_row if row_offset: self.tokens.append("\\\n" * row_offset) self.prev_col = 0 col_offset = col - self.prev_col if col_offset: self.tokens.append(" " * col_offset) def untokenize(self, iterable): it = iter(iterable) indents = [] startline = False for t in it: if len(t) == 2: self.compat(t, it) break tok_type, token, start, end, line = t if tok_type == ENDMARKER: break if tok_type == INDENT: indents.append(token) continue elif tok_type == DEDENT: indents.pop() self.prev_row, self.prev_col = end continue elif tok_type in (NEWLINE, NL): startline = True elif startline and indents: indent = indents[-1] if start[1] >= len(indent): self.tokens.append(indent) self.prev_col = len(indent) startline = False 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): indents = [] toks_append = self.tokens.append startline = token[0] in (NEWLINE, NL) prevstring = False for tok in chain([token], iterable): toknum, tokval = tok[:2] 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. 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 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 tok in 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 logical line; continuation lines are included. """ lnum = parenlev = continued = 0 namechars, numchars = string.ascii_letters + '_', '0123456789' contstr, needcont = '', 0 contline = None indents = [0] while 1: # loop over lines in stream try: line = readline() except StopIteration: line = '' 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 += 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 (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] yield (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 if start == end: continue token, initial = line[start:end], line[start] if initial in numchars or \ (initial == '.' and token != '.'): # ordinary number yield (NUMBER, token, spos, epos, line) elif initial in '\r\n': yield (NL if parenlev > 0 else NEWLINE, token, spos, epos, line) elif initial == '#': assert not token.endswith("\n") 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] 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 yield (STRING, token, spos, epos, line) elif initial in namechars: # ordinary name yield (NAME, token, spos, epos, line) elif initial == '\\': # continued stmt continued = 1 else: if initial in '([{': parenlev += 1 elif initial in ')]}': parenlev -= 1 yield (OP, token, spos, epos, line) else: yield (ERRORTOKEN, line[pos], (lnum, pos), (lnum, pos+1), line) pos += 1 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)
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