Re: Questions on completion

On Mon Oct 30 2017 Basil L. Contovounesios wrote:
> I keep records with full names (titles, middle names, etc.)
> in multiple scripts (Latin and Greek), but in emails I
> prefer to use abbreviated Latinised names, as they both are
> more universal and look better in my MUA.  I found the
> mail-name xfield to be a convenient place to store these.

Thank you, I see your point.  (I might do a similar thing in your
situation.)

> and advise bbdb-complete-mail to first pass the candidates it
> offers through bbdb-mua-summary-unify.

How does this go?  Is there a hook I overlooked?

(bbdb-complete-mail is not the most userfriendly piece of code if
you want to achieve something that is not yet implemented as an
option.)

> The only missing aspect of this approach is offering Latinised
> mail-names as completion candidates.

This can be implemented:

mail-name becomes another element of bbdb-completion-list.
Then these mail names must be hashed in bbdb-hashtable so that they
become available for completion.

(Please give me some time.)

> AFAICT, Emacs now provides two standard, high-level and
> configurable interfaces to arbitrary completion: in-buffer
> completion via completion-at-point/completion-in-region and
> minibuffer completion via completing-read.
> 
> At first glance, bbdb-complete-mail seems to emulate some of
> the work completion-at-point/completion-in-region
> could/should be doing, e.g. managing the *Completions*
> buffer.  Though I am not particularly familiar with the
> code, I have a feeling that bbdb-complete-mail could be
> simplified if it were refactored to use one of these
> built-in functions instead.

The general problem I see is that bbdb-complete-mail (and likewise
bbdb-completing-read-mails) is not performing ordinary completion.
In that sense, you could call these function names misnomers.  You
can type "Joh" to get John Smith's email address in BBDB
"[email protected]".  So what you type and what you get in the end can
be very different stories.  Also, bbdb-complete-mail provides
"cycling":  if you already have "[email protected]" and you run
bbdb-cmplete-mail again (because John Smith has multiple email
addresses in his BBDB record), you may get "[email protected]".

I am not aware of other emacs functions providing such behavior, nor
am I aware of other scenarios where such a behavior would be useful,
nor do I know how such behavior could be combined with other
completion frontends.  (I do not know anything about the frontends
you mentioned.)

Roland