/++
  read configuration files<BR>
  - read config files<BR>
  ao_config_files.d
+/
template SiSUconfigIn() {
  private import
    std.exception,
    std.stdio,
    std.utf,
    std.conv : to;
  private
  struct ConfigIn {
    private import std.file;
    final private string readInConfigFile(string conf_sdl) {
      string dot_pwd = chainPath(to!string(environment["PWD"]), ".sisu").array;
      string underscore_pwd = chainPath(to!string(environment["PWD"]), "_sisu").array;
      string dot_home = chainPath(to!string(environment["HOME"]), ".sisu").array;
      string[] possible_config_path_locations = [
        dot_pwd,
        underscore_pwd,
        dot_home,
        "/etc/sisu"
      ];
      string config_file_str;
      foreach(pth; possible_config_path_locations) {
        auto conf_file = format(
          "%s/%s",
          pth,
          conf_sdl,
        );
        try {
          if (exists(conf_file)) {
            debug(configfile) {
              writeln(conf_file);
            }
            config_file_str = readText(conf_file);
            break;
          }
        }
        catch (ErrnoException ex) {
        }
        catch (FileException ex) {
        }
      }
      return config_file_str;
    }
  }
}
/+

+/
template SiSUconfigSDLang() {
  struct ConfigSDLangRootTag {
    private auto configSDLangRootTag(string configuration, string conf_sdl_filename) {
      Tag sdl_root_conf;
      try {
        sdl_root_conf = parseSource(configuration);
      }
      catch(ParseException e) {
        stderr.writeln("SDLang problem with content for ", conf_sdl_filename);
        stderr.writeln(e.msg);
      }
      debug(sdlang) {
        Value output_dir_structure_by = sdl_root_conf.tags["output_dir_structure_by"][0].values[0];
        assert(output_dir_structure_by.type == typeid(string));
        writeln(output_dir_structure_by);
        writeln("conf SDL:");
        writeln(sdl_root_conf.toSDLDocument());
      }
      return sdl_root_conf;
    }
  }
}
/+

+/
template SiSUconfigSDLangHub() {
  mixin SiSUconfigIn;
  mixin SiSUconfigSDLang;
  struct ConfigHub {
    final private auto configSDLang(string conf_sdl) {
      auto conf_get = ConfigIn();
      auto configuration = conf_get.readInConfigFile(conf_sdl);
      auto conf = ConfigSDLangRootTag();
      auto sdl_root = conf.configSDLangRootTag(configuration, conf_sdl);
      return sdl_root;
    }
  }
}