diff options
-rw-r--r-- | Lib/shlex.py | 83 |
1 files changed, 66 insertions, 17 deletions
diff --git a/Lib/shlex.py b/Lib/shlex.py index c1ee02d..95d08d2 100644 --- a/Lib/shlex.py +++ b/Lib/shlex.py @@ -1,16 +1,19 @@ """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 import sys class shlex: "A lexical analyzer class for simple shell-like syntaxes." - def __init__(self, instream=None): + def __init__(self, instream=None, infile=None): if instream: self.instream = instream + self.infile = infile else: self.instream = sys.stdin + self.infile = None self.commenters = '#' self.wordchars = 'abcdfeghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789_' self.whitespace = ' \t\r\n' @@ -20,37 +23,76 @@ class shlex: self.lineno = 1 self.debug = 0 self.token = '' + self.filestack = [] + 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 "Pushing " + tok + if self.debug >= 1: + print "shlex: pushing token " + `tok` self.pushback = [tok] + self.pushback; def get_token(self): - "Get a token from the input stream (or from stack if it's monempty)" + "Get a token from the input stream (or from stack if it's nonempty)" if self.pushback: tok = self.pushback[0] self.pushback = self.pushback[1:] - if (self.debug >= 1): - print "Popping " + tok + if self.debug >= 1: + print "shlex: popping token " + `tok` return tok + # No pushback. Get a token. + raw = self.read_token() + # Handle inclusions + while raw == self.source: + (newfile, newstream) = self.sourcehook(self.read_token()) + self.filestack = [(self.infile,self.instream,self.lineno)] + self.filestack + self.infile = newfile + self.instream = newstream + self.lineno = 1 + if self.debug: + print 'shlex: pushing to file %s' % (self.infile,) + raw = self.get_token() + # Maybe we got EOF instead? + while raw == "": + if len(self.filestack) == 0: + return "" + else: + self.instream.close() + (self.infile, self.instream, self.lineno) = self.filestack[0] + self.filestack = self.filestack[1:] + if self.debug: + print 'shlex: popping to %s, line %d' % (self.instream, self.lineno) + self.state = ' ' + raw = self.get_token() + # Neither inclusion nor EOF + if self.debug >= 1: + if raw: + print "shlex: token=" + `raw` + else: + print "shlex: token=EOF" + return raw + + def read_token(self): + "Read a token from the input stream (no pushback or inclusions)" 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) + print "shlex: in state " + repr(self.state) + " I see character: " + repr(nextchar) if self.state == None: - return '' + 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 "I see whitespace in whitespace state" + print "shlex: I see whitespace in whitespace state" if self.token: break # emit current token else: @@ -81,7 +123,7 @@ class shlex: break elif nextchar in self.whitespace: if self.debug >= 2: - print "I see whitespace in word state" + print "shlex: I see whitespace in word state" self.state = ' ' if self.token: break # emit current token @@ -95,26 +137,33 @@ class shlex: else: self.pushback = [nextchar] + self.pushback if self.debug >= 2: - print "I see punctuation in word state" + 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.debug >= 1: - print "Token: " + result + if self.debug > 1: + if result: + print "shlex: raw token=" + `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] + return (newfile, open(newfile, "r")) + if __name__ == '__main__': lexer = shlex() while 1: tt = lexer.get_token() - if tt != None: - print "Token: " + repr(tt) - else: + print "Token: " + repr(tt) + if not tt: break |