ref: 78a6eb52c8a8b5c05305e847a4cb78360e8dba5d
dir: /sys/lib/python/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'
import string, re
from token import *
import token
__all__ = [x for x in dir(token) if x[0] != '_'] + ["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[0-7]*[lL]?'
Decnumber = r'[1-9]\d*[lL]?'
Intnumber = group(Hexnumber, 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("[uU]?[rR]?'''", '[uU]?[rR]?"""')
# Single-line ' or " string.
String = group(r"[uU]?[rR]?'[^\n'\\]*(?:\\.[^\n'\\]*)*'",
r'[uU]?[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"[uU]?[rR]?'[^\n'\\]*(?:\\.[^\n'\\]*)*" +
group("'", r'\\\r?\n'),
r'[uU]?[rR]?"[^\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))
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,
'r': None, 'R': None, 'u': None, 'U': None}
triple_quoted = {}
for t in ("'''", '"""',
"r'''", 'r"""', "R'''", 'R"""',
"u'''", 'u"""', "U'''", 'U"""',
"ur'''", 'ur"""', "Ur'''", 'Ur"""',
"uR'''", 'uR"""', "UR'''", 'UR"""'):
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"' ):
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
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)
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.
Round-trip invariant:
# 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
"""
startline = False
indents = []
toks = []
toks_append = toks.append
for tok in iterable:
toknum, tokval = tok[:2]
if toknum in (NAME, NUMBER):
tokval += ' '
if toknum == INDENT:
indents.append(tokval)
continue
elif toknum == DEDENT:
indents.pop()
continue
elif toknum in (NEWLINE, COMMENT, NL):
startline = True
elif startline and indents:
toks_append(indents[-1])
startline = False
toks_append(tokval)
return ''.join(toks)
def generate_tokens(readline):
"""
The generate_tokens() 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 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 = 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 line[pos] in '#\r\n': # skip comments or blank lines
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
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 (parenlev > 0 and NL or NEWLINE,
token, spos, epos, line)
elif initial == '#':
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 = parenlev + 1
elif initial in ')]}': parenlev = parenlev - 1
yield (OP, token, spos, epos, line)
else:
yield (ERRORTOKEN, line[pos],
(lnum, pos), (lnum, pos+1), line)
pos = 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)