Re: Mixed L2R and R2L paragraphs and horizontal scroll

> From: Richard Stallman <[email protected]>
> CC: [email protected], [email protected], [email protected],
> 	[email protected]
> Date: Sat, 06 Feb 2010 17:55:25 -0500
> 
>     > > You didn't say what to do when the (to be introduced) ``line length''
>     > > variable is nil.
>     > 
>     > Wouldn't that be window-width?
> 
>     Maybe, but I'm not sure.  Richard, could you please elaborate on your
>     suggestion?
> 
> I am not entirely sure what the issue is.
> 
> Perhaps it is my suggestion to create a variable to control where the
> right margin should be for R2L lines.  I don't remember all the
> details, but if it's an integer, that value should be the column at
> which the beginning of an R2L line appears.  When it is nil, use the
> window width (same as now).

This means we need to allow scroll either left or right past the point
where the first character is at the window's edge.  That is,
window-hscroll will no longer return only zero or positive values.  Is
that reasonable?