Re: [PATCH] Re: Duration dots and Bar lines on custom Staves.

[Joe Neeman]

On Sun, 2008-08-10 at 01:06 +0100, Neil Puttock wrote:
> 2008/8/9 Han-Wen Nienhuys <address@hidden>:
> > This does not make sense to me at all.  line-positions is a property
> > of the staff symbol, as is line-count.  If someone is calling
> >
> >  Staff_symbol::on_line(x, y)
> >
> > where x is not in fact the staff-symbol, then that is an error in the 
> > caller.
> 
> It's only called indirectly through Staff_symbol_referencer::on_line ().
> 
> Before the patch was applied, Staff_symbol_referencer::on_line ()
> looked like this:
> 
> bool
> Staff_symbol_referencer::on_line (Grob *me, int pos)
> {
>    int sz = line_count (me) - 1;
>    return ((pos + sz) % 2) == 0;
> }
> 
> Though it's called by objects which aren't staff-symbol,
> Staff_symbol_referencer::line_count () made sure it retrieved the
> staff-symbol, if present:
> 
> int
> Staff_symbol_referencer::line_count (Grob *me)
> {
>    Grob *st = get_staff_symbol (me);
>    return st ? Staff_symbol::line_count (st) : 0;
> }

I think Han-Wen's point is that the first argument to
Staff_symbol::some_function(Grob *me, ...) should always be a staff
symbol (whereas the first argument to
Staff_symbol_referencer::some_function(Grob *me, ...) should be a staff
symbol referencer).

In other words, the old code was ok but it isn't ok for
Staff_symbol::on_line to accept something that isn't a staff symbol.

Joe