bug#12811: 24.3.50; `scroll-up/down-aggressively' don't seem to work as expected

[Dani Moncayo]

>> >> So I'd like to make this request:
>> >> * Make obsolete the variables `scroll-up/down-aggressively'.
>> >> * Extend the semantics of the variable `scroll-step' to accept also a
>> >> fractional number between 0 and 1, so that for example 0.7 would mean:
>> >> "when point moves out, try to get it back into view by scrolling
>> >> up/down an amount equal to the 70% of the height of the window.  If
>> >> that fails, center in the window the line where point is".
>> >
>> > Wouldn't this keep the same semantics, but in one variable instead of
>> > 3?
>>
>> Not exactly: The functionality behind `scroll-up/down-aggressively'
>> (as explained in the manual) make no sense in some cases (after doing
>> a "big jump"), and is similar in spirit to the functionality behind
>> `scroll-step' in the other cases (after doing a "small jump").
>
> Sorry, I see no difference.

This is the difference:
* For small jumps of point, both `scroll-up/down-aggressively' and
`scroll-step' provide a similar way of bringing point back into view.
They just measure the amount of scrolling in different units.
* But for large jumps, while the `scroll-step' semantics do a suitable
thing (i.e. display the current line centered), the semantics behind
`scroll-up/down-aggressively' do an undesirable thing (i.e. don't
display the current line centered).

So, I don't see how someone would want to use
`scroll-up/down-aggressively' at all.  They do a good thing only in
some situations (small jumps), but not in other common situations
(large jumps, as when Isearching or when doing 'M-g g' for example).

Then, given that these two variables are unsuitable, let's mark them
obsolete, no?  Nobody should miss them, because the good part of their
behavior would be available in `scroll-step' (just give it the
suitable fractional value).

I hope that now my proposal is better understood.

(Regarding your fix, I'll test it and report the results when the
emacs-24 branch is merged with the trunk)

-- 
Dani Moncayo