source file: /System/Library/Frameworks/Python.framework/Versions/2.3/lib/python2.3/tokenize.py
file stats: 168 lines, 67 executed: 39.9% covered
   1. """Tokenization help for Python programs.
   2. 
   3. generate_tokens(readline) is a generator that breaks a stream of
   4. text into Python tokens.  It accepts a readline-like method which is called
   5. repeatedly to get the next line of input (or "" for EOF).  It generates
   6. 5-tuples with these members:
   7. 
   8.     the token type (see token.py)
   9.     the token (a string)
  10.     the starting (row, column) indices of the token (a 2-tuple of ints)
  11.     the ending (row, column) indices of the token (a 2-tuple of ints)
  12.     the original line (string)
  13. 
  14. It is designed to match the working of the Python tokenizer exactly, except
  15. that it produces COMMENT tokens for comments and gives type OP for all
  16. operators
  17. 
  18. Older entry points
  19.     tokenize_loop(readline, tokeneater)
  20.     tokenize(readline, tokeneater=printtoken)
  21. are the same, except instead of generating tokens, tokeneater is a callback
  22. function to which the 5 fields described above are passed as 5 arguments,
  23. each time a new token is found."""
  24. 
  25. __author__ = 'Ka-Ping Yee <ping@lfw.org>'
  26. __credits__ = \
  27.     'GvR, ESR, Tim Peters, Thomas Wouters, Fred Drake, Skip Montanaro'
  28. 
  29. import string, re
  30. from token import *
  31. 
  32. import token
  33. __all__ = [x for x in dir(token) if x[0] != '_'] + ["COMMENT", "tokenize",
  34.            "generate_tokens", "NL"]
  35. del x
  36. del token
  37. 
  38. COMMENT = N_TOKENS
  39. tok_name[COMMENT] = 'COMMENT'
  40. NL = N_TOKENS + 1
  41. tok_name[NL] = 'NL'
  42. N_TOKENS += 2
  43. 
  44. def group(*choices): return '(' + '|'.join(choices) + ')'
  45. def any(*choices): return group(*choices) + '*'
  46. def maybe(*choices): return group(*choices) + '?'
  47. 
  48. Whitespace = r'[ \f\t]*'
  49. Comment = r'#[^\r\n]*'
  50. Ignore = Whitespace + any(r'\\\r?\n' + Whitespace) + maybe(Comment)
  51. Name = r'[a-zA-Z_]\w*'
  52. 
  53. Hexnumber = r'0[xX][\da-fA-F]*[lL]?'
  54. Octnumber = r'0[0-7]*[lL]?'
  55. Decnumber = r'[1-9]\d*[lL]?'
  56. Intnumber = group(Hexnumber, Octnumber, Decnumber)
  57. Exponent = r'[eE][-+]?\d+'
  58. Pointfloat = group(r'\d+\.\d*', r'\.\d+') + maybe(Exponent)
  59. Expfloat = r'\d+' + Exponent
  60. Floatnumber = group(Pointfloat, Expfloat)
  61. Imagnumber = group(r'\d+[jJ]', Floatnumber + r'[jJ]')
  62. Number = group(Imagnumber, Floatnumber, Intnumber)
  63. 
  64. # Tail end of ' string.
  65. Single = r"[^'\\]*(?:\\.[^'\\]*)*'"
  66. # Tail end of " string.
  67. Double = r'[^"\\]*(?:\\.[^"\\]*)*"'
  68. # Tail end of ''' string.
  69. Single3 = r"[^'\\]*(?:(?:\\.|'(?!''))[^'\\]*)*'''"
  70. # Tail end of """ string.
  71. Double3 = r'[^"\\]*(?:(?:\\.|"(?!""))[^"\\]*)*"""'
  72. Triple = group("[uU]?[rR]?'''", '[uU]?[rR]?"""')
  73. # Single-line ' or " string.
  74. String = group(r"[uU]?[rR]?'[^\n'\\]*(?:\\.[^\n'\\]*)*'",
  75.                r'[uU]?[rR]?"[^\n"\\]*(?:\\.[^\n"\\]*)*"')
  76. 
  77. # Because of leftmost-then-longest match semantics, be sure to put the
  78. # longest operators first (e.g., if = came before ==, == would get
  79. # recognized as two instances of =).
  80. Operator = group(r"\*\*=?", r">>=?", r"<<=?", r"<>", r"!=",
  81.                  r"//=?",
  82.                  r"[+\-*/%&|^=<>]=?",
  83.                  r"~")
  84. 
  85. Bracket = '[][(){}]'
  86. Special = group(r'\r?\n', r'[:;.,`]')
  87. Funny = group(Operator, Bracket, Special)
  88. 
  89. PlainToken = group(Number, Funny, String, Name)
  90. Token = Ignore + PlainToken
  91. 
  92. # First (or only) line of ' or " string.
  93. ContStr = group(r"[uU]?[rR]?'[^\n'\\]*(?:\\.[^\n'\\]*)*" +
  94.                 group("'", r'\\\r?\n'),
  95.                 r'[uU]?[rR]?"[^\n"\\]*(?:\\.[^\n"\\]*)*' +
  96.                 group('"', r'\\\r?\n'))
  97. PseudoExtras = group(r'\\\r?\n', Comment, Triple)
  98. PseudoToken = Whitespace + group(PseudoExtras, Number, Funny, ContStr, Name)
  99. 
 100. tokenprog, pseudoprog, single3prog, double3prog = map(
 101.     re.compile, (Token, PseudoToken, Single3, Double3))
 102. endprogs = {"'": re.compile(Single), '"': re.compile(Double),
 103.             "'''": single3prog, '"""': double3prog,
 104.             "r'''": single3prog, 'r"""': double3prog,
 105.             "u'''": single3prog, 'u"""': double3prog,
 106.             "ur'''": single3prog, 'ur"""': double3prog,
 107.             "R'''": single3prog, 'R"""': double3prog,
 108.             "U'''": single3prog, 'U"""': double3prog,
 109.             "uR'''": single3prog, 'uR"""': double3prog,
 110.             "Ur'''": single3prog, 'Ur"""': double3prog,
 111.             "UR'''": single3prog, 'UR"""': double3prog,
 112.             'r': None, 'R': None, 'u': None, 'U': None}
 113. 
 114. triple_quoted = {}
 115. for t in ("'''", '"""',
 116.           "r'''", 'r"""', "R'''", 'R"""',
 117.           "u'''", 'u"""', "U'''", 'U"""',
 118.           "ur'''", 'ur"""', "Ur'''", 'Ur"""',
 119.           "uR'''", 'uR"""', "UR'''", 'UR"""'):
 120.     triple_quoted[t] = t
 121. single_quoted = {}
 122. for t in ("'", '"',
 123.           "r'", 'r"', "R'", 'R"',
 124.           "u'", 'u"', "U'", 'U"',
 125.           "ur'", 'ur"', "Ur'", 'Ur"',
 126.           "uR'", 'uR"', "UR'", 'UR"' ):
 127.     single_quoted[t] = t
 128. 
 129. tabsize = 8
 130. 
 131. class TokenError(Exception): pass
 132. 
 133. class StopTokenizing(Exception): pass
 134. 
 135. def printtoken(type, token, (srow, scol), (erow, ecol), line): # for testing
 136.     print "%d,%d-%d,%d:\t%s\t%s" % \
 137.         (srow, scol, erow, ecol, tok_name[type], repr(token))
 138. 
 139. def tokenize(readline, tokeneater=printtoken):
 140.     """
 141.     The tokenize() function accepts two parameters: one representing the
 142.     input stream, and one providing an output mechanism for tokenize().
 143. 
 144.     The first parameter, readline, must be a callable object which provides
 145.     the same interface as the readline() method of built-in file objects.
 146.     Each call to the function should return one line of input as a string.
 147. 
 148.     The second parameter, tokeneater, must also be a callable object. It is
 149.     called once for each token, with five arguments, corresponding to the
 150.     tuples generated by generate_tokens().
 151.     """
 152.     try:
 153.         tokenize_loop(readline, tokeneater)
 154.     except StopTokenizing:
 155.         pass
 156. 
 157. # backwards compatible interface
 158. def tokenize_loop(readline, tokeneater):
 159.     for token_info in generate_tokens(readline):
 160.         tokeneater(*token_info)
 161. 
 162. def generate_tokens(readline):
 163.     """
 164.     The generate_tokens() generator requires one argment, readline, which
 165.     must be a callable object which provides the same interface as the
 166.     readline() method of built-in file objects. Each call to the function
 167.     should return one line of input as a string.
 168. 
 169.     The generator produces 5-tuples with these members: the token type; the
 170.     token string; a 2-tuple (srow, scol) of ints specifying the row and
 171.     column where the token begins in the source; a 2-tuple (erow, ecol) of
 172.     ints specifying the row and column where the token ends in the source;
 173.     and the line on which the token was found. The line passed is the
 174.     logical line; continuation lines are included.
 175.     """
 176.     lnum = parenlev = continued = 0
 177.     namechars, numchars = string.ascii_letters + '_', '0123456789'
 178.     contstr, needcont = '', 0
 179.     contline = None
 180.     indents = [0]
 181. 
 182.     while 1:                                   # loop over lines in stream
 183.         line = readline()
 184.         lnum = lnum + 1
 185.         pos, max = 0, len(line)
 186. 
 187.         if contstr:                            # continued string
 188.             if not line:
 189.                 raise TokenError, ("EOF in multi-line string", strstart)
 190.             endmatch = endprog.match(line)
 191.             if endmatch:
 192.                 pos = end = endmatch.end(0)
 193.                 yield (STRING, contstr + line[:end],
 194.                            strstart, (lnum, end), contline + line)
 195.                 contstr, needcont = '', 0
 196.                 contline = None
 197.             elif needcont and line[-2:] != '\\\n' and line[-3:] != '\\\r\n':
 198.                 yield (ERRORTOKEN, contstr + line,
 199.                            strstart, (lnum, len(line)), contline)
 200.                 contstr = ''
 201.                 contline = None
 202.                 continue
 203.             else:
 204.                 contstr = contstr + line
 205.                 contline = contline + line
 206.                 continue
 207. 
 208.         elif parenlev == 0 and not continued:  # new statement
 209.             if not line: break
 210.             column = 0
 211.             while pos < max:                   # measure leading whitespace
 212.                 if line[pos] == ' ': column = column + 1
 213.                 elif line[pos] == '\t': column = (column/tabsize + 1)*tabsize
 214.                 elif line[pos] == '\f': column = 0
 215.                 else: break
 216.                 pos = pos + 1
 217.             if pos == max: break
 218. 
 219.             if line[pos] in '#\r\n':           # skip comments or blank lines
 220.                 yield ((NL, COMMENT)[line[pos] == '#'], line[pos:],
 221.                            (lnum, pos), (lnum, len(line)), line)
 222.                 continue
 223. 
 224.             if column > indents[-1]:           # count indents or dedents
 225.                 indents.append(column)
 226.                 yield (INDENT, line[:pos], (lnum, 0), (lnum, pos), line)
 227.             while column < indents[-1]:
 228.                 indents = indents[:-1]
 229.                 yield (DEDENT, '', (lnum, pos), (lnum, pos), line)
 230. 
 231.         else:                                  # continued statement
 232.             if not line:
 233.                 raise TokenError, ("EOF in multi-line statement", (lnum, 0))
 234.             continued = 0
 235. 
 236.         while pos < max:
 237.             pseudomatch = pseudoprog.match(line, pos)
 238.             if pseudomatch:                                # scan for tokens
 239.                 start, end = pseudomatch.span(1)
 240.                 spos, epos, pos = (lnum, start), (lnum, end), end
 241.                 token, initial = line[start:end], line[start]
 242. 
 243.                 if initial in numchars or \
 244.                    (initial == '.' and token != '.'):      # ordinary number
 245.                     yield (NUMBER, token, spos, epos, line)
 246.                 elif initial in '\r\n':
 247.                     yield (parenlev > 0 and NL or NEWLINE,
 248.                                token, spos, epos, line)
 249.                 elif initial == '#':
 250.                     yield (COMMENT, token, spos, epos, line)
 251.                 elif token in triple_quoted:
 252.                     endprog = endprogs[token]
 253.                     endmatch = endprog.match(line, pos)
 254.                     if endmatch:                           # all on one line
 255.                         pos = endmatch.end(0)
 256.                         token = line[start:pos]
 257.                         yield (STRING, token, spos, (lnum, pos), line)
 258.                     else:
 259.                         strstart = (lnum, start)           # multiple lines
 260.                         contstr = line[start:]
 261.                         contline = line
 262.                         break
 263.                 elif initial in single_quoted or \
 264.                     token[:2] in single_quoted or \
 265.                     token[:3] in single_quoted:
 266.                     if token[-1] == '\n':                  # continued string
 267.                         strstart = (lnum, start)
 268.                         endprog = (endprogs[initial] or endprogs[token[1]] or
 269.                                    endprogs[token[2]])
 270.                         contstr, needcont = line[start:], 1
 271.                         contline = line
 272.                         break
 273.                     else:                                  # ordinary string
 274.                         yield (STRING, token, spos, epos, line)
 275.                 elif initial in namechars:                 # ordinary name
 276.                     yield (NAME, token, spos, epos, line)
 277.                 elif initial == '\\':                      # continued stmt
 278.                     continued = 1
 279.                 else:
 280.                     if initial in '([{': parenlev = parenlev + 1
 281.                     elif initial in ')]}': parenlev = parenlev - 1
 282.                     yield (OP, token, spos, epos, line)
 283.             else:
 284.                 yield (ERRORTOKEN, line[pos],
 285.                            (lnum, pos), (lnum, pos+1), line)
 286.                 pos = pos + 1
 287. 
 288.     for indent in indents[1:]:                 # pop remaining indent levels
 289.         yield (DEDENT, '', (lnum, 0), (lnum, 0), '')
 290.     yield (ENDMARKER, '', (lnum, 0), (lnum, 0), '')
 291. 
 292. if __name__ == '__main__':                     # testing
 293.     import sys
 294.     if len(sys.argv) > 1: tokenize(open(sys.argv[1]).readline)
 295.     else: tokenize(sys.stdin.readline)