== site.pp ==
include "classes/*"
include "nodes/*"

== classes/a.pp ==
class a {
  exec { "touch-foo":

  }

== classes/b.pp ==
class b {
  file { "/etc/config.txt":
    ensure => "present",
      content => "somestuff",
      notify => Exec["touch-foo"],
      # Could not find dependent Exec["touch-foo"]
      # notify => a::Exec["touch-foo"],
      # Syntax error at '::Exec'; expected '}'
    }
   }
}


== host01.pp ==
node ""host01" {
  include a
  include b
}