# -*- coding: iso-8859-1 -*- | |
"""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.path | |
import sys | |
from collections import deque | |
try: | |
from cStringIO import StringIO | |
except ImportError: | |
from StringIO import StringIO | |
__all__ = ["shlex", "split"] | |
class shlex: | |
"A lexical analyzer class for simple shell-like syntaxes." | |
def __init__(self, instream=None, infile=None, posix=False): | |
if isinstance(instream, basestring): | |
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 | |
if self.debug: | |
print 'shlex: reading from %s, line %d' \ | |
% (self.instream, self.lineno) | |
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, basestring): | |
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, basestring) 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) | |
if __name__ == '__main__': | |
if len(sys.argv) == 1: | |
lexer = shlex() | |
else: | |
file = sys.argv[1] | |
lexer = shlex(open(file), file) | |
while 1: | |
tt = lexer.get_token() | |
if tt: | |
print "Token: " + repr(tt) | |
else: | |
break |