Function _make_line

Lib/difflib.py:1403–1457

Returns line of text with user's change markup and line formatting. lines -- list of lines from the ndiff generator to produce a line of text from. When producing the line of text to return, the lines used are removed from this list. format_key --

(lines, format_key, side, num_lines=[0,0])

    diff_lines_iterator = ndiff(fromlines,tolines,linejunk,charjunk)

    def _make_line(lines, format_key, side, num_lines=[0,0]):
        """Returns line of text with user's change markup and line formatting.

        lines -- list of lines from the ndiff generator to produce a line of
                 text from.  When producing the line of text to return, the
                 lines used are removed from this list.
        format_key -- '+' return first line in list with "add" markup around
                          the entire line.
                      '-' return first line in list with "delete" markup around
                          the entire line.
                      '?' return first line in list with add/delete/change
                          intraline markup (indices obtained from second line)
                      None return first line in list with no markup
        side -- indice into the num_lines list (0=from,1=to)
        num_lines -- from/to current line number.  This is NOT intended to be a
                     passed parameter.  It is present as a keyword argument to
                     maintain memory of the current line numbers between calls
                     of this function.

        Note, this function is purposefully not defined at the module scope so
        that data it needs from its parent function (within whose context it
        is defined) does not need to be of module scope.
        """
        num_lines[side] += 1
        # Handle case where no user markup is to be added, just return line of
        # text with user's line format to allow for usage of the line number.
        if format_key is None:
            return (num_lines[side],lines.pop(0)[2:])
        # Handle case of intraline changes
        if format_key == '?':
            text, markers = lines.pop(0), lines.pop(0)
            # find intraline changes (store change type and indices in tuples)
            sub_info = []
            def record_sub_info(match_object,sub_info=sub_info):
                sub_info.append([match_object.group(1)[0],match_object.span()])
                return match_object.group(1)
            change_re.sub(record_sub_info,markers)
            # process each tuple inserting our special marks that won't be
            # noticed by an xml/html escaper.
            for key,(begin,end) in reversed(sub_info):
                text = text[0:begin]+'\0'+key+text[begin:end]+'\1'+text[end:]
            text = text[2:]
        # Handle case of add/delete entire line
        else:
            text = lines.pop(0)[2:]
            # if line of text is just a newline, insert a space so there is
            # something for the user to highlight and see.
            if not text:
                text = ' '
            # insert marks that won't be noticed by an xml/html escaper.
            text = '\0' + format_key + text + '\1'
        # Return line of text, first allow user's line formatter to do its
        # thing (such as adding the line number) then replace the special
        # marks with what the user's change markup.
        return (num_lines[side],text)

    def _line_iterator():
        """Yields from/to lines of text with a change indication.