Re: [elpa] externals/ebdb 9e7a96f: Add experimental ebdb-completion-at-point-function

[Eric Abrahamsen <eric@ericabrahamsen.net>]

Eric Abrahamsen <eric@ericabrahamsen.net> writes:

> Stefan Monnier <monnier@IRO.UMontreal.CA> writes:
>
>>> +;; Experimental completion-at-point function.  I'm not sure this is a
>>> +;; good idea yet -- with a large enough EBDB database, nearly any
>>> +;; string is completable, meaning the other completion-at-point
>>> +;; functions will rarely get a chance.
>>> +(defun ebdb-completion-at-point-function ()
>> [...]
>>> +    (when completions
>>> +      (list start (point)
>>> +	    (mapcar
>>> +	     (lambda (str)
>>> +	       ;; Gross.
>>> +	       (if (string-match-p "@" str)
>>> +		   str
>>> +		 (capitalize str)))
>>> +	     completions)
>>> +	    '(:exclusive no)))))
>> Completion-at-point-functions are expected to be cheap/fast (it's normal
>> to call it in post-command-hook) and in order to work correctly the
>> completion table it returns should ideally not depend on the text
>> between START and END (i.e. it's OK to look at the text between
>> START..END in order to choose between an email completion table and
>> a file completion table, but it shouldn't throw away emails just
>> because they don't seem to match the text between START..END).
>>
>> Also in order to be effective, you want them to be selective, e.g. only
>> match when we're pretty sure that the completion-table we return is
>> relevant (e.g. we're on a "To:" line in a message-mode buffer), so it
>> usually depends on the major mode in which it's used.
>>
>> EBDB might elect not to provide a completion-at-point-function but
>> instead to provide only a completion-table (or a bunch of completion
>> tables).  Then message-mode could use that completion-table when it
>> determines that we're completing an email address.

[...]

> My only reservation is that BBDB/EBDB mail completion first completes a
> contact mail address, and subsequently cycles through that contact's
> other addresses. Is this something that the standard mechanisms can
> replicate?

Never mind, obviously the completion functions can do whatever they like
with the string to be completed.