Re: `gnus-unseen-mark' everywhere

[prj@po.cwru.edu (Paul Jarc)]

Simon Josefsson <jas@extundo.com> wrote:
> If a article is seen or not is determined by Gnus.

Yes, but I'm thinking of a user who doesn't care whether Gnus thinks
it has seen the article before, and might find the "seen" mark a
convenient way of representing some other information instead.

> Now, seen marks might be stored in the backend but if the backend
> would start to modify the value, it would have the same semantics as
> recent, no?

I think that would depend on what sort of action would automatically
set or unset the mark, if any.

> Well, OK, a backend could use different algorithms for deciding which
> articles are seen and which are recent, but then we would have to
> invent another mark that reflects Gnus's opinion and not the
> backend's.

No, users who like "seen" the way it is would simply not abuse it to
make it mean something different.  If backends were to store "seen"
marks, but never change them automatically, then the semantics would
be unaffected.

> I'm not sure that having two backend-controlled marks that indicate
> readedness is needed.

If the mark is being abused, then it may well have nothing to do with
readness.

> Right, seen is used as an indicator to the user to display what Gnus
> thinks of the article.  Recent is used as an indicator to the user to
> display what the backend thinks of the article.

If the user is in control of the marks, then the marks mean whatever
the user wants them to mean.  (But that includes the possibility of
the meanings you describe, if that's what the user wants.)

>> - Gnus does not make it easy for the user to define arbitrary new mark
>>   types.
>
> I think it is pretty easy.  Just write a command, jas-add-flonk-mark,
> that adds a mark to the current article (using either the backend
> interface or modifying the group info or modifying a summary local
> variable, depending on what you want).  Then write a summary buffer %U
> function to display the mark.

Ah, I didn't know that.  But are we sure that no part of Gnus will
break when finding a mark it has never heard of?  And does the manual
say we can rely on that?

>> a user might want to adjust the meaning of "seen" in such a way
>> that the backend could have the most up-to-date copy.
>
> Isn't controlling the recent mark in the backend enough?

User-defined marks are enough.  "Recent" is partly under the control
of the server behind the backend (when there is one), so it might not
be easily subverted.

> Just write a function that queries the user for a name of the mark and
> set it.  I guess Group Info wasn't made to support this usage, but the
> only problem would be slowing things down.  If another data structure
> for group info was used, it would be fast.

What's wrong with the group info data structure?  Why would it be any
slower for user-defined marks than for standard marks?


paul