bug#373: scroll-up, scroll-down don't respect current column

[Joe Wells <jbw@macs.hw.ac.uk>]

jidanni@jidanni.org writes:

> The nerve of scroll-up and scroll-down, always putting the cursor back
> in column 0 no matter what column we were in. There should be a
> variable to control this, documented in scroll-up and scroll-down's
> docstrings. Same with scroll-*-*mark.
>
> Test in a buffer made with (compile "yes 01234567|sed 333q").

WARNING: The behavior you request can be seriously problematic in
buffers with long lines.  Suppose you are at column 378952 (yes, this
happened to me two days ago) and you scroll forward.  First, I hope if
the scrolling keeps you on the same line, the column tracking would
not be so stupid as to take you back to where you were.  Suppose you
were near the end of the (very long) line and a new line was
displayed.  Suppose this new line had 9191917 columns.  Should we
really go to column 378952 on the new line?  The standard (and quite
useful) behavior of scroll forward is to display another screenful of
material, regardless of whether it is on a new line or not.  Your
proposed behavior would really break this.

Just a cautionary note.

-- 
Joe


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