[Email-SIG] API for Header objects [was: Dropping bytes "support" in json]

[R. David Murray]

On Sat, 18 Apr 2009 at 00:13, Stephen J. Turnbull wrote:
> R. David Murray writes:
>
> > put Header objects into it.  I don't think the "overhead" of
> > having to do
> >
> >      message['Subject'] = Header('subject string')
>
> Hm.  Should a Header know which header it is?  Ie, should that be
>
>    message['Subject'] = Header('subject', 'subject string')
>
> ?  (I assume you would be less than in love with having the assignment
> magically stuffing "Subject" into the Header as it gets assigned.)

Hmm.  Probably.  But:

     message.addHeader(Header('subject', 'subject string'))

would seem sensible.  That looses the nice collections interface...but
if a Header knows its keyword then it makes sense.

However, I'm not convinced a Header should know its keyword.  After all,
the only difference between a From: header and a To: header is the
keyword, and one can easily imagine wanting to do something like:

     replymessage['to'] = frommessage['from']

--David