/++
  extract native/orig header return associative array<BR>

  the header is passed as text (lopped off top of a sisu markup file until the
  required first heading ^A~), determine whether is a native header or sdlang one
  with a regex check if whether it contains the "native header" required tag/field
  @title: then process accordingly as a "native header" or "sdlang header"
  converting the metadata and make instructions to a common json format used by
  program internally. Moved to associative array.
+/
template SiSUheaderExtractHub() {
  private import
    std.exception,
    std.regex,
    std.stdio,
    std.traits,
    std.typecons,
    std.utf,
    std.conv : to;
  private import sdlang;
  private import
    ao_rgx,
    ao_conf_make_meta_native,
    ao_conf_make_meta_sdlang;
  mixin SiSUrgxInit;
  mixin SiSUheaderExtractNative;
  mixin SiSUheaderExtractSDLang;
  auto rgx = Rgx();
  auto SiSUheaderExtractHub(Src, DocMake)(
    Src     header_src,
    DocMake conf_doc_make_aa
  ) {
    debug(asserts){
      static assert(is(typeof(header_src)       == char[]));
      static assert(is(typeof(conf_doc_make_aa) == string[string][string]));
    }
    auto head_native = HeaderDocMetadataAndMakeNativeToAA();
    auto head_sdlang = HeaderExtractSDL();
    auto header_make_and_meta_tuple = (match(header_src, rgx.native_header_meta_title))
    ? (head_native.headerNativeToAA(header_src))
    : (head_sdlang.headerSDLangToAA(header_src, conf_doc_make_aa));
    static assert(!isTypeTuple!(header_make_and_meta_tuple));
    static assert(header_make_and_meta_tuple.length==2);
    return header_make_and_meta_tuple;
  }
}