Execute HQ9+

Implement a HQ9+ interpreter or compiler for Rosetta Code.

The function below executes a HQ9+ program and returns the program output as a string. <lang javascript>function hq9plus(code) {

 var out = ;
 var acc = 0;
 
 for (var i=0; i<code.length; i++) {
   switch (code.charAt(i)) {
     case 'H': out += "hello, world\n"; break;
     case 'Q': out += code + "\n"; break;
     case '9':
       for (var j=99; j>1; j--) {
         out += j + " bottles of beer on the wall, " + j + " bottles of beer.\n";
         out += "Take one down and pass it around, " + (j-1) + " bottles of beer.\n\n";
       }
       out += "1 bottle of beer on the wall, 1 bottle of beer.\n" +
           "Take one down and pass it around, no more bottles of beer on the wall.\n\n" +
           "No more bottles of beer on the wall, no more bottles of beer.\n" +
           "Go to the store and buy some more, 99 bottles of beer on the wall.\n";
       break;
     case '+': acc++; break;
   }
 }
 return out;

}</lang>