Any way to adjust difflib algorithm?

[Grant Edwards]

I'm trying to use difflib to compare two files, and it's not
producing very useful results.  When comparing two lines where
only a few characters have changed, it usually seems to decide
that a line was deleted/inserted/replaced rather than changed.

Here's how I'm using it:

   #!/usr/bin/python
   import sys,difflib
   
   fromlines = [l.rstrip('\n') for l in open(sys.argv[1]).readlines()]
   tolines   = [l.rstrip('\n') for l in open(sys.argv[2]).readlines()]
   
   print difflib.HtmlDiff().make_file(fromlines,tolines)
   
In my particular usage, no lines have ever been
inserted/deleted, so perhaps I should be running diffs on
individual lines instead?  If I do that, I can't figure out how
to generate HTML output.

Is there a way to tell the differ to try harder to match lines?

-- 
Grant Edwards                   grante             Yow! I hope something GOOD
                                  at               came in the mail today so
                               visi.com            I have a REASON to live!!