Re: [External] : Re: completing-read depricated initial-input

[Tassilo Horn <tsdh@gnu.org>]

Drew Adams <drew.adams@oracle.com> writes:

>> You have to delete the initial input if it's not what
>> you want or if you want to see the other possibilities.
>
> That's akin to the arguments pro/con `delete-selection-mode'.

No, not really.  It is easy for every user to enable or disable
delete-selection-mode.  That's not true for initial-input.  If the
programmer used it, you get it, and there's no easy way to disable it.

>> So basically all occurrences
>
> "Basically"? or "all"?  Do you mean not all
> but most/generally?  Or do you mean all, so
> not just basically?
>
> I guess you mean almost all, aka _not_ all.

Yes, I've meant that I cannot think of a situation where initial-input
used as a default value is suitable and even in non-default-value
scenarios I was able to come up with only two sensible use-cases.  And
honestly, only the completing-read-multiple case is really convincing to
me.

>> where INITIAL-INPUT is used as a kind of default
>> value are better handled with the DEF argument.
>
> Sounds a bit circular.  That just says that DEF
> is a better default-value behavior.  Initial
> input isn't the same as a default value.  The
> behavior/effect is different.

Yes.  What I've meant to say is that in the past, initial-input was
frequently used as a means to insert a default value, maybe because it
was available earlier.  I don't know exactly, I'm an emacs newby using
it only since 2001.

And since it comes first in the completing-read argument list and
INITIAL-INPUT is more in the face than DEF, chances are that people read
it first, it looks suitable, and so it is used for the default value
case.

>> The only places where I can see it's useful is when all possible
>> completions have a common prefix and that is given as initial-input
>> (but then you only save one TAB) or with completing-read-multiple
>> when it's highly likely that the user wants to use the defaults given
>> as initial-input and just insert some more.
>> (completing-read-multiple doesn't explicitly state that INITIAL-INPUT
>> is deprecated.)
>
> The behavior of INITIAL-INPUT differs from that
> of DEF.  That's enough to point to different uses.
>
> Unless, that is, you can convince all that the
> DEF behavior is always preferable - for all users,
> all calls to `completing-read', and all contexts.

I can only say that except for the crm case I cannot come up with a good
example where it's useful.  But if you know some, I'm eager to read
them.

And in any case: there's no need to have flamewars about some argument
being called deprecated.  It's one of the central functions in emacs,
the argument is in the middle of the argument list.  There's no doubt it
will still be there in 20 years. ;-)

Bye,
Tassilo