>> In the example below, I want to set the markup property `bar` as a
>> tweak to influence `\foo`.
>
> you could of course do something like
>
> %%%
> #(define-markup-command (foo-markup layout props) ()
> #:properties ((bar #f) (details '()))
> (interpret-markup
> layout props
> #{
> \markup \fontsize #(or bar (assoc-get 'bar (assoc-get 'props details
> '()) 10)) \natural
> #}))
>
> foo =
> #(define-music-function () ()
> #{
> \tweak parent-alignment-X #CENTER
> \tweak self-alignment-X #CENTER
> -\markup \foo-markup
> #})
>
> {
> f'2-\foo
> f'2-\tweak details.props.bar #5 \foo
> }
> %%%
Ah, yes, I forgot that it is possible to extend the `props` alist.
Thanks a lot!
Werner
