More elegant solution for diffing two sequences

[Ulrich Eckhardt]

Hi!

I'm trying to write some code to diff two fonts. What I have is every 
character (glyph) of the two fonts in a list. I know that the list is sorted 
by the codepoints of the characters. What I'd like to ask is whether there 
is a more elegant solution to the loop below or whether there are any rough 
corners in my code (see below). Note that I'm targeting Python 2, not 3 yet.

Thank you!

Uli


def diff_font(font1, font2):
    it1 = iter(font1.glyphs)
    it2 = iter(font2.glyphs)
    try:
        glyph1 = it1.next()
        glyph2 = it2.next()
        while True:
            if glyph1.codepoint < glyph2.codepoint:
                # glyph only in first font
                diff_glyph(glyph1, None)
                glyph1 = it1.next()
            elif glyph2.codepoint < glyph2.codepoint:
                # glyph only in second font
                diff_glyph(None, glyph2)
                glyph2 = it2.next()
            else:
                # glyph in both fonts
                diff_glyph(glyph1, glyph2)
                glyph1 = it1.next()
                glyph2 = it2.next()
    except StopIteration, msg:
        # remaining glyphs in either font are exclusive to that font
        for glyph in it1:
            diff_glyph(glyph, None)
        for glyph in it1:
            diff_glyph(None, glyph)