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