cpython/Lib/tokenize.py

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# This module compiles a regular expression that recognizes Python tokens.
# It is designed to match the working of the Python tokenizer exactly.
# It takes care of everything except indentation;
# note that un-escaped newlines are tokens, too.
# tokenprog.regs[3] gives the location of the token without whitespace
# It also defines various subexpressions, but doesn't compile them.
# See the function test() below for an example of how to use.
import regex
# Note: to get a quoted backslash in a regexp, it must be quadrupled.
Ignore = '[ \t]*\(\\\\\n[ \t]*\)*\(#.*\)?'
Name = '[a-zA-Z_][a-zA-Z0-9_]*'
Hexnumber = '0[xX][0-9a-fA-F]*[lL]?'
Octnumber = '0[0-7]*[lL]?'
Decnumber = '[1-9][0-9]*[lL]?'
Intnumber = Hexnumber + '\|' + Octnumber + '\|' + Decnumber
Exponent = '[eE][-+]?[0-9]+'
Pointfloat = '\([0-9]+\.[0-9]*\|\.[0-9]+\)\(' + Exponent + '\)?'
Expfloat = '[0-9]+' + Exponent
Floatnumber = Pointfloat + '\|' + Expfloat
Number = Floatnumber + '\|' + Intnumber
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String = '\'\(\\\\.\|[^\\\n\']\)*\''
Operator = '~\|\+\|-\|\*\|/\|%\|\^\|&\||\|<<\|>>\|==\|<=\|<>\|!=\|>=\|=\|<\|>'
Bracket = '[][(){}]'
Special = '[:;.,`\n]'
Funny = Operator + '\|' + Bracket + '\|' + Special
PlainToken = Name + '\|' + Number + '\|' + String + '\|' + Funny
Token = Ignore + '\(' + PlainToken + '\)'
try:
save_syntax = regex.set_syntax(0) # Use default syntax
tokenprog = regex.compile(Token)
finally:
if save_syntax != 0:
dummy = regex.set_syntax(save_syntax) # Restore original syntax
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def test(file):
f = open(file, 'r')
while 1:
line = f.readline()
if not line: break
i, n = 0, len(line)
while i < n:
j = tokenprog.match(line, i)
if j < 0:
print 'No token at', `line[i:i+20]` + '...'
i = i+1
else:
i = i+j
a, b = tokenprog.regs[3]
if a < b:
print 'Token:', `line[a:b]`