"concatenating" tweaks

[Kieren MacMillan]

Hello all,

The following works great:

%%%%  SNIPPET BEGINS
\version "2.19"

tweaked-spanner =
  \tweak color #red
  \startTextSpan

music = {
  c''1\tweaked-spanner 1\stopTextSpan
}

\score { \music }
%%%%  SNIPPET ENDS

Now I want to have a number of different tweaked spanners which share a bunch 
of tweaks. But the intuitive (?) extension doesn’t work:

%%%%  SNIPPET BEGINS
\version "2.19"

shared-tweaks =
  \tweak fontsize #12

tweaked-spanner =
  \shared-tweaks
  \tweak color #red
  \startTextSpan

music = {
  c''1\tweaked-spanner 1\stopTextSpan
}

\score { \music }
%%%%  SNIPPET ENDS

Can anything be done to make this work as intended/expected?
n.b. I’d rather not build a music function here, unless the benefits are quite 
apparent, e.g. if I could write

    c’’1\tweaked-spanner #KANGA #ROO

where KANGA and ROO are two markups that get used in the [post-event] function.

Thanks,
Kieren.
________________________________

Kieren MacMillan, composer
‣ website: www.kierenmacmillan.info
‣ email: address@hidden