12.5.1 Context evaluation

Contexts can be modified during interpretation with Scheme code. The syntax for this is

\applyContext function

function should be a Scheme function taking a single argument, being the context to apply it to. The following code will print the current bar number on the standard output during the compile:

\applyContext
  #(lambda (x)
    (format #t "\nWe were called in barnumber ~a.\n"
     (ly:context-property x 'currentBarNumber)))