gistfile1.txt

class klass {
 file { ['/tmp/a']: ensure => present }
}

define def_file() {
 include klass

 file { $name:
  ensure => present,
  require => File['/tmp/a']
 }
}

def_file { '/tmp/b': }

def_file { '/tmp/c': require => File['/tmp/b'] }