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118 lines
4.1 KiB
Python
118 lines
4.1 KiB
Python
# Module and documentation by Eric S. Raymond, 21 Dec 1998
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import sys, os, string
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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):
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if instream:
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self.instream = instream
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else:
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self.instream = sys.stdin
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self.commenters = '#'
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self.wordchars = 'abcdfeghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789_'
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self.whitespace = ' \t\r\n'
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self.quotes = '\'"'
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self.state = ' '
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self.pushback = [];
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self.lineno = 1
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self.debug = 0
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self.token = ''
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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 "Pushing " + tok
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self.pushback = [tok] + self.pushback;
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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 monempty)"
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if self.pushback:
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tok = self.pushback[0]
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self.pushback = self.pushback[1:]
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if (self.debug >= 1):
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print "Popping " + tok
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return tok
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tok = ''
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while 1:
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nextchar = self.instream.read(1);
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if nextchar == '\n':
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self.lineno = self.lineno + 1
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if self.debug >= 3:
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print "In state " + repr(self.state) + " I see character: " + repr(nextchar)
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if self.state == None:
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return ''
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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 "I see whitespace in whitespace state"
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if self.token:
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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 = self.lineno + 1
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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.quotes:
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self.token = nextchar
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self.state = nextchar
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else:
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self.token = nextchar
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if self.token:
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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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self.token = self.token + nextchar
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if nextchar == self.state:
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self.state = ' '
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break
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elif self.state == 'a':
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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 "I see whitespace in word state"
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self.state = ' '
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if self.token:
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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 = self.lineno + 1
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elif nextchar in self.wordchars or nextchar in self.quotes:
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self.token = self.token + nextchar
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else:
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self.pushback = [nextchar] + self.pushback
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if self.debug >= 2:
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print "I see punctuation in word state"
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self.state = ' '
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if self.token:
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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.debug >= 1:
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print "Token: " + result
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return result
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if __name__ == '__main__':
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lexer = shlex()
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while 1:
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tt = lexer.get_token()
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if tt != None:
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print "Token: " + repr(tt)
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else:
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break
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