[Email-SIG] header folding

[R. David Murray]

Well, my big project still hasn't kicked off, so I'm still working on email6.

I just posted a new blog post:

    http://www.bitdance.com/blog/2011/07/25_01_email6_pypi_release/

The PyPI release is old news here.  The interesting part of the post
for this group is the discussion of the new header folding API at
the end.  Basically, BaseHeader gets a 'wrap' method, and there is
a new policy control, 'refold_source' (I'll probably rename it to
'rewrap_source', since I expect to apply it also to message bodies).
The policy control has three values: none, long, and all.  None means
never touch the source, always use it.  long means refold a header if
any if the source's component lines are longer than max_line_length.
'all' means refold everything.

Email5.1 wraps long lines, but leaves short lines alone.  Under 'long',
this code refolds the whole header if there is a long line in it.
I think that is more RFC compliant, and I don't think it will cause any
problems if used.

The default for refold_source is 'none'.  I'm considering this a bug
fix, since a stated goal of the email package is to reproduce the source
accurately if possible.

(Currently the new code still calls Header to do the folding; writing
the new folder is my next task.)

--
R. David Murray           http://www.bitdance.com