rfc822.Message mapping interface

[Barry A. Warsaw]

>>>>> "PM" == Postal Meowbot <meowbot at meowing.net> writes:

    PM> According to The Friendly Manual, Message objects from the
    PM> rfc822 module offer a read-only mapping interface to the
    PM> headers.  In real life, __delitem__ and __setitem__ methods
    PM> exist and even do something useful (very useful for the
    PM> application at hand).

    PM> In this case, does it mean these methods are internal and may
    PM> disappear some day, or just that the docs want updating?

I think it's just that the docs need updating.  I suggest the
paragraph in

    http://www.python.org/doc/current/lib/message-objects.html

be changed slightly like so:

    Message instances also support a limited mapping interface. In
    particular: m[name] is like m.getheader(name) but raises KeyError
    if there is no matching header; and len(m), m.has_key(name),
    m.keys(), m.values() and m.items() act as expected (and
    consistently).  Message instances also support the mapping
    writeable interface m[name]=value and del m[name].

It might also make sense to mention that some mapping methods aren't
supported, e.g. update(), get(), popitem(), clear(), copy(),
setdefault().

    PM> The fate of civiliation is safe in either case.  I'm only
    PM> trying to learn if it makes sense to maintain private copies
    PM> of rfc822 and mimetools for futureproofing purposes.

If you're doing MIME, please check out http://sf.net/projects/mimelib
for a candidate of a next generation replacement for mimetools,
rfc822, MIMEWriter, etc.  I've got a small backlog of updates to the
code there that I'll try to check in shortly.

-Barry