Setting default_factory of defaultdict to key

[Dave Angel]

On 12/07/2014 11:43 AM, Shiyao Ma wrote:
> On Dec 07 at 11:31 -0500, Dave Angel wrote:
>> Since this clearly is intended to be part of the earlier thread, please make
>> it so by using reply-list or whatever equivalent your email program has.
>
> Kinda OT. But interested what's the difference between reply-list and to.
> In addition, based on what information a thread is formed?
>

Each email program uses different buttons and/or menu items to enable 
the user.  So I'm using button names from Thunderbird, but most email 
programs should have equivalent.

WHen I use "Write", a new message is composed, and I get to fill in the 
subject line, the to: field, etc.  Such a message always starts a new 
thread.

When I use Reply-list, there is a field within the header of the new 
message that refers to the previous one.  That's in addition to the 
automatic filling in of the subj: line with a "Re:", any quoting that 
may occur, etc.  I also could use Reply-All, and trim out the private 
recipients.  But reply-list is easier, and more likely to end up correct.

There is a LOT of information in those headers, and I'm not sure just 
which one is filled in to make threading work.  I'm assuming it's the 
"References:" field.  If you want to see the headers (and the 
body/bodies), you can use (in Thunderbird) the
   View->Message Source

menu item.

For example in the message you just sent, there are 104 lines before it 
gets to the first par of your actual message body.  That's almost 6k of 
stuff.

Anyway, when I display the messages, they're shown in a hierarchical 
tree.  It's hard to imagine reading a newsgroup like this without that, 
although I did in the early 80's, under MSDOS.  I wrote a utility which 
sorted the messages by subject line, and at least I tended to see 
related messages together (except that already-read messages were only 
visible by search, and if somebody changed the subject line, the thread 
was (for me only) broken.




-- 
DaveA