# File lib/asciidoctor/document.rb, line 545
  def apply_attribute_value_subs(value)
    if value.match(REGEXP[:pass_macro_basic])
      # copy match for Ruby 1.8.7 compat
      m = $~
      subs = []
      if !m[1].empty?
        subs = resolve_subs(m[1])
      end
      if !subs.empty?
        apply_subs(m[2], subs)
      else
        m[2]
      end
    else
      apply_header_subs(value)
    end
  end