class Sprockets::DirectiveProcessor

def compile_header_pattern(comments)

of code will not be processed.
Directives in comments after the first non-whitespace line

Ruby (#) comments are supported.
of the source file. C style (/* */), JavaScript (//), and
Directives will only be picked up if they are in the header 
def compile_header_pattern(comments)
  re = comments.map { |c|
    case c
    when String
      "(?:#{Regexp.escape(c)}.*\\n?)+"
    when Array
      "(?:#{Regexp.escape(c[0])}(?m:.*?)#{Regexp.escape(c[1])})"
    else
      raise TypeError, "unknown comment type: #{c.class}"
    end
  }.join("|")
  Regexp.compile("\\A(?:(?m:\\s*)(?:#{re}))+")
end