16        line-by-line syntax: strip comments (as long as "#" is your
18        escaping the newline (ie. backslash at end of line), strip
23        report physical line number, even if the logical line in question
25        implementing line-at-a-time lookahead.
41            strip from "#" to end-of-line, as well as any whitespace
44            strip leading whitespace from each line before returning it
46            strip trailing whitespace (including line terminator!) from
47            each line before returning it
54            if a backslash is the last non-newline character on a line
55            after stripping comments and whitespace, join the following line
56            to it to form one "logical line"; if N consecutive lines end
58            form one logical line.
66        None for end-of-file: an empty string might just be a blank line (or
67        an all-whitespace line), if 'rstrip_ws' is true but 'skip_blanks' is
126            (filename, current line number)."""
134     def gen_error (self, msg, line=None):  argument
136         if line is None:
137             line = self.current_line
139         if isinstance(line, (list, tuple)):
140             outmsg.append("lines %d-%d: " % tuple (line))
142             outmsg.append("line %d: " % line)
147     def error (self, msg, line=None):  argument
148         raise ValueError, "error: " + self.gen_error(msg, line)
150     def warn (self, msg, line=None):  argument
152            line in the current file.  If the current logical line in the
154            whole range, eg. "lines 3-5".  If 'line' supplied, it overrides
155            the current line number; it may be a list or tuple to indicate a
157            line."""
158         sys.stderr.write("warning: " + self.gen_error(msg, line) + "\n")
162         """Read and return a single logical line from the current file (or
166            single string.  Updates the current line number, so calling
168            line(s) just read.  Returns None on end-of-file, since the empty
177             line = self.linebuf[-1]
179             return line
184             # read the line, make it None if EOF
185             line = self.file.readline()
186             if line == '': line = None
188             if self.strip_comments and line:
190                 # Look for the first "#" in the line.  If none, never
196                 # lurking in there) and otherwise leave the line alone.
198                 pos = line.find("#")
204                 elif pos == 0 or line[pos-1] != "\\":
208                     # (NB. this means that if the final line is all comment
211                     eol = (line[-1] == '\n') and '\n' or ''
212                     line = line[0:pos] + eol
214                     # If all that's left is whitespace, then skip line
221                     if line.strip() == "":
225                     line = line.replace("\\#", "#")
228             # did previous line end with a backslash? then accumulate
231                 if line is None:
232                     self.warn ("continuation line immediately precedes "
237                     line = line.lstrip()
238                 line = buildup_line + line
240                 # careful: pay attention to line number when incrementing it
246             # just an ordinary line, read it as usual
248                 if line is None:        # eof
251                 # still have to be careful about incrementing the line number!
261                 line = line.strip()
263                 line = line.lstrip()
265                 line = line.rstrip()
267             # blank line (whether we rstrip'ed or not)? skip to next line
269             if (line == '' or line == '\n') and self.skip_blanks:
273                 if line[-1] == '\\':
274                     buildup_line = line[:-1]
277                 if line[-2:] == '\\\n':
278                     buildup_line = line[0:-2] + '\n'
282             return line
293             line = self.readline()
294             if line is None:
296             lines.append (line)
299     def unreadline (self, line):  argument
300         """Push 'line' (a string) onto an internal buffer that will be
302            a parser with line-at-a-time lookahead."""
304         self.linebuf.append (line)