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shlex.split(): Passing None for s argument now raises an exception, rather than reading sys.stdin. The feature was deprecated in Python 3.9.
349 lines
13 KiB
Python
349 lines
13 KiB
Python
"""A lexical analyzer class for simple shell-like syntaxes."""
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# Module and documentation by Eric S. Raymond, 21 Dec 1998
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# Input stacking and error message cleanup added by ESR, March 2000
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# push_source() and pop_source() made explicit by ESR, January 2001.
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# Posix compliance, split(), string arguments, and
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# iterator interface by Gustavo Niemeyer, April 2003.
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# changes to tokenize more like Posix shells by Vinay Sajip, July 2016.
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import os
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import re
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import sys
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from collections import deque
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from io import StringIO
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__all__ = ["shlex", "split", "quote", "join"]
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class shlex:
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"A lexical analyzer class for simple shell-like syntaxes."
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def __init__(self, instream=None, infile=None, posix=False,
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punctuation_chars=False):
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if isinstance(instream, str):
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instream = StringIO(instream)
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if instream is not None:
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self.instream = instream
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self.infile = infile
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else:
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self.instream = sys.stdin
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self.infile = None
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self.posix = posix
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if posix:
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self.eof = None
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else:
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self.eof = ''
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self.commenters = '#'
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self.wordchars = ('abcdfeghijklmnopqrstuvwxyz'
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'ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789_')
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if self.posix:
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self.wordchars += ('ßàáâãäåæçèéêëìíîïðñòóôõöøùúûüýþÿ'
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'ÀÁÂÃÄÅÆÇÈÉÊËÌÍÎÏÐÑÒÓÔÕÖØÙÚÛÜÝÞ')
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self.whitespace = ' \t\r\n'
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self.whitespace_split = False
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self.quotes = '\'"'
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self.escape = '\\'
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self.escapedquotes = '"'
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self.state = ' '
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self.pushback = deque()
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self.lineno = 1
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self.debug = 0
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self.token = ''
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self.filestack = deque()
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self.source = None
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if not punctuation_chars:
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punctuation_chars = ''
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elif punctuation_chars is True:
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punctuation_chars = '();<>|&'
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self._punctuation_chars = punctuation_chars
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if punctuation_chars:
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# _pushback_chars is a push back queue used by lookahead logic
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self._pushback_chars = deque()
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# these chars added because allowed in file names, args, wildcards
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self.wordchars += '~-./*?='
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#remove any punctuation chars from wordchars
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t = self.wordchars.maketrans(dict.fromkeys(punctuation_chars))
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self.wordchars = self.wordchars.translate(t)
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@property
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def punctuation_chars(self):
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return self._punctuation_chars
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def push_token(self, tok):
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"Push a token onto the stack popped by the get_token method"
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if self.debug >= 1:
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print("shlex: pushing token " + repr(tok))
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self.pushback.appendleft(tok)
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def push_source(self, newstream, newfile=None):
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"Push an input source onto the lexer's input source stack."
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if isinstance(newstream, str):
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newstream = StringIO(newstream)
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self.filestack.appendleft((self.infile, self.instream, self.lineno))
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self.infile = newfile
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self.instream = newstream
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self.lineno = 1
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if self.debug:
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if newfile is not None:
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print('shlex: pushing to file %s' % (self.infile,))
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else:
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print('shlex: pushing to stream %s' % (self.instream,))
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def pop_source(self):
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"Pop the input source stack."
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self.instream.close()
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(self.infile, self.instream, self.lineno) = self.filestack.popleft()
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if self.debug:
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print('shlex: popping to %s, line %d' \
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% (self.instream, self.lineno))
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self.state = ' '
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def get_token(self):
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"Get a token from the input stream (or from stack if it's nonempty)"
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if self.pushback:
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tok = self.pushback.popleft()
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if self.debug >= 1:
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print("shlex: popping token " + repr(tok))
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return tok
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# No pushback. Get a token.
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raw = self.read_token()
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# Handle inclusions
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if self.source is not None:
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while raw == self.source:
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spec = self.sourcehook(self.read_token())
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if spec:
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(newfile, newstream) = spec
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self.push_source(newstream, newfile)
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raw = self.get_token()
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# Maybe we got EOF instead?
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while raw == self.eof:
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if not self.filestack:
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return self.eof
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else:
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self.pop_source()
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raw = self.get_token()
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# Neither inclusion nor EOF
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if self.debug >= 1:
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if raw != self.eof:
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print("shlex: token=" + repr(raw))
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else:
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print("shlex: token=EOF")
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return raw
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def read_token(self):
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quoted = False
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escapedstate = ' '
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while True:
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if self.punctuation_chars and self._pushback_chars:
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nextchar = self._pushback_chars.pop()
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else:
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nextchar = self.instream.read(1)
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if nextchar == '\n':
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self.lineno += 1
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if self.debug >= 3:
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print("shlex: in state %r I see character: %r" % (self.state,
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nextchar))
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if self.state is None:
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self.token = '' # past end of file
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break
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elif self.state == ' ':
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if not nextchar:
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self.state = None # end of file
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break
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elif nextchar in self.whitespace:
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if self.debug >= 2:
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print("shlex: I see whitespace in whitespace state")
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if self.token or (self.posix and quoted):
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break # emit current token
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else:
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continue
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elif nextchar in self.commenters:
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self.instream.readline()
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self.lineno += 1
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elif self.posix and nextchar in self.escape:
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escapedstate = 'a'
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self.state = nextchar
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elif nextchar in self.wordchars:
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self.token = nextchar
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self.state = 'a'
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elif nextchar in self.punctuation_chars:
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self.token = nextchar
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self.state = 'c'
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elif nextchar in self.quotes:
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if not self.posix:
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self.token = nextchar
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self.state = nextchar
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elif self.whitespace_split:
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self.token = nextchar
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self.state = 'a'
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else:
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self.token = nextchar
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if self.token or (self.posix and quoted):
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break # emit current token
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else:
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continue
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elif self.state in self.quotes:
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quoted = True
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if not nextchar: # end of file
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if self.debug >= 2:
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print("shlex: I see EOF in quotes state")
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# XXX what error should be raised here?
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raise ValueError("No closing quotation")
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if nextchar == self.state:
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if not self.posix:
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self.token += nextchar
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self.state = ' '
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break
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else:
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self.state = 'a'
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elif (self.posix and nextchar in self.escape and self.state
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in self.escapedquotes):
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escapedstate = self.state
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self.state = nextchar
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else:
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self.token += nextchar
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elif self.state in self.escape:
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if not nextchar: # end of file
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if self.debug >= 2:
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print("shlex: I see EOF in escape state")
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# XXX what error should be raised here?
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raise ValueError("No escaped character")
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# In posix shells, only the quote itself or the escape
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# character may be escaped within quotes.
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if (escapedstate in self.quotes and
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nextchar != self.state and nextchar != escapedstate):
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self.token += self.state
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self.token += nextchar
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self.state = escapedstate
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elif self.state in ('a', 'c'):
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if not nextchar:
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self.state = None # end of file
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break
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elif nextchar in self.whitespace:
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if self.debug >= 2:
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print("shlex: I see whitespace in word state")
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self.state = ' '
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if self.token or (self.posix and quoted):
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break # emit current token
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else:
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continue
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elif nextchar in self.commenters:
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self.instream.readline()
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self.lineno += 1
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if self.posix:
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self.state = ' '
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if self.token or (self.posix and quoted):
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break # emit current token
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else:
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continue
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elif self.state == 'c':
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if nextchar in self.punctuation_chars:
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self.token += nextchar
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else:
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if nextchar not in self.whitespace:
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self._pushback_chars.append(nextchar)
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self.state = ' '
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break
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elif self.posix and nextchar in self.quotes:
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self.state = nextchar
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elif self.posix and nextchar in self.escape:
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escapedstate = 'a'
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self.state = nextchar
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elif (nextchar in self.wordchars or nextchar in self.quotes
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or (self.whitespace_split and
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nextchar not in self.punctuation_chars)):
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self.token += nextchar
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else:
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if self.punctuation_chars:
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self._pushback_chars.append(nextchar)
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else:
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self.pushback.appendleft(nextchar)
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if self.debug >= 2:
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print("shlex: I see punctuation in word state")
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self.state = ' '
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if self.token or (self.posix and quoted):
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break # emit current token
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else:
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continue
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result = self.token
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self.token = ''
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if self.posix and not quoted and result == '':
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result = None
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if self.debug > 1:
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if result:
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print("shlex: raw token=" + repr(result))
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else:
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print("shlex: raw token=EOF")
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return result
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def sourcehook(self, newfile):
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"Hook called on a filename to be sourced."
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if newfile[0] == '"':
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newfile = newfile[1:-1]
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# This implements cpp-like semantics for relative-path inclusion.
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if isinstance(self.infile, str) and not os.path.isabs(newfile):
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newfile = os.path.join(os.path.dirname(self.infile), newfile)
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return (newfile, open(newfile, "r"))
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def error_leader(self, infile=None, lineno=None):
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"Emit a C-compiler-like, Emacs-friendly error-message leader."
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if infile is None:
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infile = self.infile
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if lineno is None:
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lineno = self.lineno
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return "\"%s\", line %d: " % (infile, lineno)
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def __iter__(self):
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return self
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def __next__(self):
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token = self.get_token()
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if token == self.eof:
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raise StopIteration
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return token
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def split(s, comments=False, posix=True):
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"""Split the string *s* using shell-like syntax."""
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if s is None:
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raise ValueError("s argument must not be None")
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lex = shlex(s, posix=posix)
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lex.whitespace_split = True
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if not comments:
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lex.commenters = ''
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return list(lex)
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def join(split_command):
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"""Return a shell-escaped string from *split_command*."""
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return ' '.join(quote(arg) for arg in split_command)
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_find_unsafe = re.compile(r'[^\w@%+=:,./-]', re.ASCII).search
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def quote(s):
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"""Return a shell-escaped version of the string *s*."""
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if not s:
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return "''"
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if _find_unsafe(s) is None:
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return s
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# use single quotes, and put single quotes into double quotes
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# the string $'b is then quoted as '$'"'"'b'
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return "'" + s.replace("'", "'\"'\"'") + "'"
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def _print_tokens(lexer):
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while 1:
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tt = lexer.get_token()
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if not tt:
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break
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print("Token: " + repr(tt))
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if __name__ == '__main__':
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if len(sys.argv) == 1:
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_print_tokens(shlex())
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else:
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fn = sys.argv[1]
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with open(fn) as f:
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_print_tokens(shlex(f, fn))
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