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- # Module and documentation by Eric S. Raymond, 21 Dec 1998
-
- import sys, os, string
-
- class shlex:
- "A lexical analyzer class for simple shell-like syntaxes."
- def __init__(self, instream=None):
- if instream:
- self.instream = instream
- else:
- self.instream = sys.stdin
- self.commenters = '#'
- self.wordchars = 'abcdfeghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789_'
- self.whitespace = ' \t\r\n'
- self.quotes = '\'"'
- self.state = ' '
- self.pushback = [];
- self.lineno = 1
- self.debug = 0
- self.token = ''
-
- def push_token(self, tok):
- "Push a token onto the stack popped by the get_token method"
- if (self.debug >= 1):
- print "Pushing " + tok
- self.pushback = [tok] + self.pushback;
-
- def get_token(self):
- "Get a token from the input stream (or from stack if it's monempty)"
- if self.pushback:
- tok = self.pushback[0]
- self.pushback = self.pushback[1:]
- if (self.debug >= 1):
- print "Popping " + tok
- return tok
- tok = ''
- while 1:
- nextchar = self.instream.read(1);
- if nextchar == '\n':
- self.lineno = self.lineno + 1
- if self.debug >= 3:
- print "In state " + repr(self.state) + " I see character: " + repr(nextchar)
- if self.state == None:
- return ''
- elif self.state == ' ':
- if not nextchar:
- self.state = None; # end of file
- break
- elif nextchar in self.whitespace:
- if self.debug >= 2:
- print "I see whitespace in whitespace state"
- if self.token:
- break # emit current token
- else:
- continue
- elif nextchar in self.commenters:
- self.instream.readline()
- self.lineno = self.lineno + 1
- elif nextchar in self.wordchars:
- self.token = nextchar
- self.state = 'a'
- elif nextchar in self.quotes:
- self.token = nextchar
- self.state = nextchar
- else:
- self.token = nextchar
- if self.token:
- break # emit current token
- else:
- continue
- elif self.state in self.quotes:
- self.token = self.token + nextchar
- if nextchar == self.state:
- self.state = ' '
- break
- elif self.state == 'a':
- if not nextchar:
- self.state = None; # end of file
- break
- elif nextchar in self.whitespace:
- if self.debug >= 2:
- print "I see whitespace in word state"
- self.state = ' '
- if self.token:
- break # emit current token
- else:
- continue
- elif nextchar in self.commenters:
- self.instream.readline()
- self.lineno = self.lineno + 1
- elif nextchar in self.wordchars or nextchar in self.quotes:
- self.token = self.token + nextchar
- else:
- self.pushback = [nextchar] + self.pushback
- if self.debug >= 2:
- print "I see punctuation in word state"
- self.state = ' '
- if self.token:
- break # emit current token
- else:
- continue
-
- result = self.token
- self.token = ''
- if self.debug >= 1:
- print "Token: " + result
- return result
-
- if __name__ == '__main__':
-
- lexer = shlex()
- while 1:
- tt = lexer.get_token()
- if tt != None:
- print "Token: " + repr(tt)
- else:
- break
-
-