script-column: earlier scripts support later scripts; issue 3683

script-column: earlier scripts support later scripts; issue 3683

[dak, 2013-11-29 08:20:11]

https://codereview.appspot.com/35010043/diff/1/lily/script-column.cc
File lily/script-column.cc (right):

https://codereview.appspot.com/35010043/diff/1/lily/script-column.cc#newcode156
lily/script-column.cc:156: use all the scripts so far as support for the current
grob
A question of understanding: supports are not transitive automatically (if a
supports b, and b supports c, a supports c)?

Because if they are, it should be sufficient to only add all of the grobs since
the last grob with explicit outside_staff_priority.

https://codereview.appspot.com/35010043/diff/1/lily/script-column.cc#newcode159
lily/script-column.cc:159: for (SCM t = ss; scm_is_pair (t) && !scm_is_eq (t,
s); t = scm_cdr (t))
Drop the scm_is_pair (t) condition.  It can never be false, and makes the loop
more confusing to read (the condition looks like the loop skips over a->a
pairings but with cover both a->b and b->a when it doesn't).

[Keith, 2013-11-29 15:50:02]

On Fri, 29 Nov 2013 00:20:11 -0800, <dak@gnu.org> wrote:

>
https://codereview.appspot.com/35010043/diff/1/lily/script-column.cc#newcode156
> lily/script-column.cc:156: use all the scripts so far as support for the
> current grob
> A question of understanding: supports are not transitive automatically
> (if a supports b, and b supports c, a supports c)?
>
The support relationship is not intrinsically transitive.
It was effectively transitive when side-placement was one-dimensional, but no
longer with placement using skylines.  See the tracker example, where 1 supports
4, 4 supports 5.

>
https://codereview.appspot.com/35010043/diff/1/lily/script-column.cc#newcode159
> lily/script-column.cc:159: for (SCM t = ss; scm_is_pair (t) &&
> !scm_is_eq (t, s); t = scm_cdr (t))
> Drop the scm_is_pair (t) condition.  It can never be false, and makes
> the loop more confusing to read (the condition looks like the loop skips
> over a->a pairings but with cover both a->b and b->a when it doesn't).
>
Done.  That was my first inclination and I have tested it already.