bug#13055: 24.3.50; `scroll-margin' not always honored in Info buffers

[Dani Moncayo]

>> IMO, `scroll-margin' clearly makes sense whenever the displayed text
>> changes, regardless of the relation between the old displayed text and
>> the new one.
>
> You are reading into the variable a meaning it never had.

In that case, I'd like you to consider whether that meaning could make
any sense.

>> >> As I see it, this variable guarantees the users to _always_ see some
>> >> context lines around point, which is an important feature to me.
>> >
>> > No, it doesn't.
>>
>> It should.  In fact it does
>
> No, it does not.  I could show you more examples, but I don't think it
> will matter.  You won't change your mind.

I try to be as open as I can to change my mind, whenever I realize I
was wrong somehow.

>> Please Eli, reconsider this.  The meaning of `scroll-margin' makes
>> perfectly sense here.
>
> It is against my best technical judgment to make changes that spread
> the effect of scroll-related options beyond scrolling.  It would be
> one more step towards making redisplay_window, which is the main
> workhorse of the display engine, an unmaintainable heap of twisty
> little passages all alike.  We are already half way there, just take
> the hint from the fact that we need to explain in the user manual the
> order of priority between 3 options that control scrolling in
> contradicting ways.

I agree with you in that the current user-level model for customizing
automatic scrolling is too messy.  IMO, the variables
scroll-up/down-aggressively are misguided and could be obsoleted.  But
that is another story.

>  Or just read the code, if you dare, and then try
> writing a coherent description of what it does, and why.  I'm sure we
> got there by following exactly this kind of path to creeping
> featurism, accompanied all the way by requests like "please,
> pretty-please, give me just this one more little feature."

I don't know anything about how Emacs implements these features.  I
just was trying to explain, as a mere user, how I'd like Emacs to
behave, and why.  If my idea is wrong or misguided, just dismiss it.

> Anyway, I'm tired of having my arguments heard and discarded.

I'm sorry you feel that way.  I don't discard your arguments.  I just
sometimes disagree with them.

> The change that will give you what you asked for is below.  I will commit
> it -- under protest -- provided that Stefan and/or Chong give their
> blessing -- not to the changes, but to the idea of applying
> scroll-margin to this unrelated use case, and a marginal one at that.

I don't pretend to make any pressure.  You decide whether what I
propose is valid or not.

Anyway, thank you again for all the time a energy invested in Emacs;

-- 
Dani Moncayo