Re: Grobs that are their own ancestors.

[Neil Puttock]

On 15 July 2011 18:28,  <address@hidden> wrote:
> I've now gone on a quest for parental loops in the source, and I've found 
> some:
>
> chord-repetition.ly
> chord-tremolo-articulations.ly
> dynamics-alignment-breaker.ly
> dynamics-alignment-no-line.ly
> dynamics-glyphs.ly
> dynamics-line.ly
> dynamics-rest-positioning.ly
> dynamics-text-right-padding.ly
> dynamics-text-spanner-abs-dynamic.ly
>
> After this I stopped checking, but in all of these, the DynamicLineSpanner is 
> its own parent if you trace back its ancestry.

Surely these are harmless though?  We'd only be concerned if the
parentage loop is in the same axis.

> The culprit is line 179 of dynamic-align-engraver - if anyone has any 
> intuition as to why this is the case, lemme know!

set_bound () also sets the X-parent if _this_ doesn't already have one
and we're setting the left bound.

Axis_group_interface::add_element () sets the DynamicLineSpanner as
X-parent (depends on 'axes setting).

So we get the following situation:

If we acknowledge a DynamicText, set DynamicLineSpanner as Y-parent.
If the DynamicText starts a new alignment spanner, set as X-parent of
DynamicLineSpanner.

Cheers,
Neil