gistfile1.txt

use Config::Simple::Role;

class Config::Simple does Config::Simple::Role {
 
  multi method new($filename) {
    return self.bless(:filename($filename));
  }

  multi method new($filename, Str :$b) {
    my $module = "Config::Simple::$b";
    require ::($module);
    return ::($module).new($filename);
  }

  multi method read($filename) {
    my $text = slurp($filename);
    my $this = self.bless(:filename($filename), :hash(EVAL($text)));
    return $this;
  }

  method read($filename, Str :$b) {
      my $module = "Config::Simple::$b";
      require ::($module);
      return ::($module).read($filename);
  }

  method write($filename = Any) {
    $.filename = $filename if $filename.defined;
    say $.filename;
    my $fh = open $.filename, :w;
    $fh.print(%!hash.perl);
    $fh.close;
  }

}

gistfile2.txt

role Config::Simple::Role {
  has %.hash is rw;
  has $.filename is rw;

   method AT-KEY($key) {
    my $self = self;
    Proxy.new(
      FETCH => method ()
      {
        $self.hash{$key};
      },
      STORE => method ($val)
      {
        $self.set($key, $val);
      }
      );
  }
  
  method set($key, $val) {
    %.hash{$key} = $val;
  }

  method new($filename){ ... };
  
  method read($filename) { ... };
  
  method write($filename = Any) { ... };
}