Creating new operators

[Philippe Baril Lecavalier]

Dear list,

After much search, I finally found the "\repeat unfold N", but is it 
possible with scheme to create new operators, to abbreviate things?  Like 
using for that purpose "**" (since "*" is already taken) ? Or is that 
hard-coded deep in the interpreter?

Intuitively, as a beginner, I would have guessed that a4*6 would be the 
same as typing that note six times (and that's not it). So for 
simplicity, could one create a new operator through scheme, like "**"? 
Example of what I mean:

    {c8 g e g} ** 6
would amount to:
    \repeat unfold 6 {c8 g e g}

Thank you.

P.B. Lecavalier