Folder search semantics

[Rob Browning]

Austin Clements <amdragon at MIT.EDU> writes:

> As a consequence, all folders are subfolders of the inbox.  With
> recursive search, a search for your inbox folder returns *all* of your
> messages.  I wasn't trying to say that we shouldn't support recursive
> search (I'm all for flexibility), but it's a confusing default for
> Maildir++ because of this.
>
> Maildir++ has the added twist that the inbox folder has no name.  As a
> result, currently notmuch can't search for a Maildir++ inbox folder,
> which needs to be addressed somehow.  The least surprising approach
> would compatibility with the Maildir++ convention of calling the
> top-level folder INBOX, the subfolder INBOX.work, etc.

Just adding my agreement here.  With recursion and no anchors, "folder:"
really won't work for the inbox for Maildir++.

> Maildir++ issues aside, I submit that rooted, non-recursive folder
> searches are a more natural default with a more conventional syntactic
> extension to non-rooted/recursive searches.  In
> id:87aaiy3u65.fsf at yoom.home.cworth.org, you mentioned that you
> implemented non-rooted folder search to mimic subject search.  But file
> system paths are not natural language like subject lines.  File system
> paths are hierarchical and rooted.
>
> Of course, special query operators like ^ and $ can mitigate this, but
> these queries *aren't* regexps and, furthermore, people don't usually
> apply regexps to file names.  They apply globs.  Glob syntax has the
> added benefit of congruity with Xapian wildcard syntax.  This naturally
> leads to a rooted, non-recursive syntax by default (like globs), where a
> * at the end means recursive and a * at the beginning means non-rooted.
> In fact, we could easily generalize this to arbitrary shell globs.

I agree with all of this.  Something like fnmatch() sounds appropriate
to me.  In fact, I'd suggest that we implement this very much like
fnmatch() with folder references like paths -- where "/" is always the
separator, regardless of how things are handled in the underlying
storage.  So depending on the backend, foo/bar could refer to
"Maildir/foo/bar" or "Maildir/.foo.bar".

And personally, I think I'd prefer that folder: be anchored by default,
so that folder:work means "the top-level folder named work", but it's
not a big deal to me as long as there's a fairly easy way to specify
exactly what I want.

-- 
Rob Browning
rlb @defaultvalue.org and @debian.org
GPG as of 2002-11-03 14DD 432F AE39 534D B592 F9A0 25C8 D377 8C7E 73A4