Re: sorting uniquely by message-id

Hi Michael,

> I really want to just keep the copy that went through the list,
> because that's the one that went into the public archive, and replies
> will work better on that version.  But, sometimes some of the messages
> get copied to me only, and can't lose them.

So for all emails with the same message-id field, keep just the one with
a list-id field but if none of them have a list-id field then keep all
of them.

> I realized I don't want to change the order of the folder.  Instead,
> I am doing:
>
>   scan -format '%5(msg),%{message-id},%<(addr{List-Id})%>' +inbox'
>
> and then process this with Perl to do the right thing....
>
>     if(defined($msgnum{$msgid})) {
>         if(defined($msglist{$msgid})) {
>             @todelete << $msgnum;
>         } else {
>             $msglist{$msgid} = $listid;
>             push(@todelete, $msgnum{$msgid});
>         }
>     } else {
>         $msgnum{$msgid} = $msgnum;
>     }

Doesn't that add empty $listids to %msglist?  Consider this input.

    1,m,li@foo  $msgnum{'m'} = 1
    2,m         $msglist{'m'} = ''; push(@todelete, 1);

>   156 %09/16   To:"Rob Wilton      asdf.ietf.or Re: [Asdf] Robert Wilton's 
> Block
>   164 %09/17     Carsten Bormann     asdf.ietf.or Re: [Asdf] Robert Wilton's 
> Block
>   175 %09/17     "Rob Wilton                      RE: [Asdf] Robert Wilton's 
> Block
> - 176 %09/17   "Rob Wilton                      RE: [Asdf] Robert Wilton's 
> Block
>   177 %09/17   "Rob Wilton         asdf.ietf.or Re: [Asdf] Robert Wilton's 
> Block
> - 178 %09/17     Carsten Bormann                  Re: [Asdf] Robert Wilton's 
> Block
>   179 %09/17     Carsten Bormann     asdf.ietf.or Re: [Asdf] Robert Wilton's 
> Block
> - 187 %09/17       David Kemp                       Re: [Asdf] Robert 
> Wilton's Block
>   188 %09/17       David Kemp          asdf.ietf.or Re: [Asdf] Robert 
> Wilton's Block
> - 200 %09/17         Carsten Bormann                  Re: [Asdf] Robert 
> Wilton's Block
>   201 %09/17         Carsten Bormann     asdf.ietf.or Re: [Asdf] Robert 
> Wilton's Block
> - 180 %09/17   "Rob Wilton                      RE: [Asdf] Robert Wilton's 
> Block
>   181 %09/17   "Rob Wilton         asdf.ietf.or Re: [Asdf] Robert Wilton's 
> Block
> - 184 %09/17     Carsten Bormann     asdf.ietf.or Re: [Asdf] Robert Wilton's 
> Block
>   185 %09/17     Carsten Bormann                  Re: [Asdf] Robert Wilton's 
> Block
> - 189 %09/17       "Rob Wilton                      RE: [Asdf] Robert 
> Wilton's Block
>   190 %09/17       "Rob Wilton         asdf.ietf.or Re: [Asdf] Robert 
> Wilton's Block
> - 193 %09/17         Alexander Pelov                  Re: [Asdf] Robert 
> Wilton's Block
>   194 %09/17         Alexander Pelov     asdf.ietf.or Re: [Asdf] Robert 
> Wilton's Block
> - 196 %09/17         Barry Leiba                      Re: [Asdf] Robert 
> Wilton's Block
>   197 %09/17         Barry Leiba                      Re: [Asdf] Robert 
> Wilton's Block
> - 198 %09/17           "Rob Wilton         asdf.ietf.or Re: [Asdf] Robert 
> Wilton's Block
>   199 %09/17           "Rob Wilton                      RE: [Asdf] Robert 
> Wilton's Block
>   327 %09/18           Carsten Bormann                  Re: [Asdf] Robert 
> Wilton's Block

Given

    $ grep -i sequence-negation ~/.mh_profile
    sequence-negation: not

something like this might do.

    mark -seq dup -del all
    pick -seq li --list-id 'z*'
    scan -forma '%{message-id}' li |
    while read -r mi; do
        pick -nozero -seq dup --message-id "$mi" notli
    done

> I think that I ought to use something other than , that can't appear
> in any of the relevant fields.  ASCII defined this "FS" character
> (ASCII 29 or something), and I wonder why we don't use it more
> often...  i wonder if the format spec ought to make this easily
> accessible?

US should be used for the lowest level, working up through RS and GS to
FS last; ascii(7).  Here's US.

    $ fmttest -forma '%{from}'$'\c_''%{date}' -width 0 . | sed -n l
    Michael Richardson <mcr@sandelman.ca>\037Fri, 18 Sep 2020 16:36:15 -0\
    400$
    $

-- 
Cheers, Ralph.