Text spanner with middle text

[James Worlton]

Hello,

I'm trying to create a text/dynamics spanner to produce something similar to the following:

dim. - - - - al - - - - pp

I've checked the LSR, and the email archives and couldn't find a solution. David Nalesnik's function from here https://lists.gnu.org/archive/html/lilypond-user/2017-10/msg00461.html comes closest, but still is beyond my ability to tweak to the point that it does what I need.

Is there a way to do this using a single text spanner? I could probably fake it with 2 spanners, but would rather not if I didn't have to, since the positioning of the middle text would be trial and error.

Thanks,

James Worlton