function to get moment as staff-spaces

[Kieren MacMillan]

Hello all,

There are times I would like to offset something by a duration (e.g., a quarter 
note) without using spacers — for example, I have a ChordName that collides 
with a markup, and I want the ChordName to move horizontally to the right (not 
vertically***). I don't want to change the duration of the chord, or the moment 
of its attack — only its visual placement.

So I'd like to say something like

    \once \override ChordName #'X-offset = #(ly:make-moment 1 4)

Obvoiusly this doesn't work. But is there an easy function to turn the spacing 
of a moment (at the current moment) into a distance Lily can use to offset 
things?

Thanks,
Kieren.

*** The function I'm asking about would be a lot less necessary if we could 
choose the axis of adjustment for a grob involved in a collision — is that 
possible?