Determine all grob types within a music expression

[Urs Liska]

Hi all,

I want to write a function that applies certain overrides to all grobs 
within a music expression. I already have one (older) function that 
applies the override (and \revert) to *all* possible grobs (derived from 
all-grob-descriptions), but I find that pretty rough since that will 
create whole lot of overrides rather than only the 5-15 that would 
usually be necessary to catch everything in the music.

Is there a way to parse a music expression and find out all the grob 
types that happen to be inside? Of course when iterating over a music 
expression there *are* no grobs around yet, only "music". I might think 
about figuring it out from the event types, but I don't expect this to 
be reliable or efficient.

So is there any idea about what to do to make it (= overriding a 
property for all grobs that are created from the music in a music 
expression) happen?

Thanks for any suggestions
Urs