[Email-SIG] fixing the current email module

[Glenn Linderman]

On approximately 10/8/2009 3:39 PM, came the following characters from 
the keyboard of Barry Warsaw:
> On Oct 8, 2009, at 5:59 PM, Glenn Linderman wrote:
>
>> So to prepend into a text header, you shouldn't need to decode the 
>> undecodable...
>
> Except that you also have to collapse Re:'s and move them to the front 
> of the string. 

Well, that is a feature of some mailing list programs.  Those that want 
to do that, will have to decode and re-encode.

However, there are definitely mailing lists that don't do that.  Google 
Groups is one example that doesn't collapse, and always prepends the 
headers in front of Re:.  Seems like all the Python lists do the 
collapsing (I wonder why! :) )  Other lists don't do prepending (I think 
the RFCs recommend not prepending in Subject, actually), of the others 
I'm subscribed to, that prepend, some collapse and some don't.

I'm saying that there are use cases where prepending could be done 
without decoding; while you are positing use cases where that is 
insufficient, but you shouldn't have said "Except"... you should have 
said "There are also other use cases".

And when you collapse Re:, do you also collapse various 
language-specific spellings of Re: ???  that is a hard problem.

And don't forget removing the prior prepended text before adding the new 
prepended text.

Actually, as long as the prepended text is ASCII, all that work can be 
done on the encoded value.  When it is not ASCII, it may still be 
separated and recognizable.  Still that logic is more complex than 
decoding, handling as Unicode, and encoding.... when it works.  Just 
pointing out that there is more than one way to do things...

-- 
Glenn -- http://nevcal.com/
===========================
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