int clazz = pool.addClass("java/lang/StringBuffer");
int appendmethod = pool.addMethodRef(clazz, "append",
"(Ljava/lang/Object;)Ljava/lang/StringBuffer;");
code.anew(clazz);
code.dup();
code.invokespecial(pool.addMethodRef(clazz, "<init>", "()V"));
int n = childs();
for(int i=0; i<n; i++) {
getChild(i).compile(context, GET);
code.invokevirtual(appendmethod);
}