automatic setting of `currentBarNumber'

[Werner LEMBERG]

The following problem:

  \score {
    \relative {
      c1 | c1 | c1 | c1 |        % Bars 1-4
  }

  \score {
    \relative {
      c1 | c1 | c1 | c1 |        % Bars 5-8
  }

I know how to manually set `currentBarNumber' in the second \score
block:

  \set Score.currentBarNumber = #5

However, I want to have this set automatically; for example, if I
later decide to insert two bars into the first \score block, the
starting bar number for the second \score block should be updated
accordingly.

It's rather straightforward to store the value of `currentBarNumber'
in a Scheme variable (the number `10' is just a dummy value):

  #(define lastBarNumber 10)

  \score {
    \relative {
      c1 | d1 | e1 | f1 |
    \applyContext
      #(lambda (x)
        (set! lastBarNumber (ly:context-property x 'currentBarNumber)))
  }

However, I wasn't able to make lilypond use the computed value.  I
tried both `\set' and `\applyContext' (using
`ly:context-set-property!') without success.

Please advise.


    Werner