Re: Fix #5964: MM Rests shouldn’t segfault when there’s no StaffSymbol. (issue 576090043 by address@hidden)

[Carl . D . Sorensen]

Here's a thought.


https://codereview.appspot.com/576090043/diff/557790043/lily/multi-measure-rest.cc
File lily/multi-measure-rest.cc (right):

https://codereview.appspot.com/576090043/diff/557790043/lily/multi-measure-rest.cc#newcode268
lily/multi-measure-rest.cc:268: bool oneline = (!staff) ||
Staff_symbol::line_positions (staff).size() == 1;
On 2020/05/07 15:12:03, Valentin Villenave wrote:
> On 2020/05/07 12:18:48, Dan Eble wrote:
> > If there is no staff symbol, then there isn't even one line. Are you
sure you
> > don't want this?
> >     bool oneline = staff ? /*etc.*/ : false;
> 
> No, I actually want oneline to be true . I did consider changing the
variable
> name to no_multiple_lines, because that’s what it’s really about. I
also
> considered adding a comment such as:
> // If there is no StaffSymbol, print MMrests on one (invisible) line.
> 
> > Incidentally, I am surprised to see the amount of work involved in
determining
> > whether the staff has one line.  It's not the kind of thing one
expects to
> > involve heap allocation.
> 
> I suspect this sort-of mirrors the way you’d do it in Scheme:
> (if (> (length
>         (ly:grob-property
>          (ly:grob-object grob 'staff-symbol)
>         'line-positions))
>       0)
>  etc.
> 
> If you have a simpler syntax in mind, please share :-)
> 
> Cheers,
> -- V.

What about changing the name from oneline to specialcase?  Or maybe
default_position?  Then it would naturally apply to both no staff symbol
and one-line staff symbol.

https://codereview.appspot.com/576090043/