ParseBodyVisitor pbv=isOutput?new ParseBodyVisitor():null;
if(isOutput)pbv.visitBegin(bc);
// Query query=pc.getQuery(@query);
tag.setQuery(adapter.newLocal(Types.QUERY));
adapter.loadArg(0);
Expression val = tag.getAttribute("query").getValue();
val.writeOut(bc, Expression.MODE_REF);
if(val instanceof LitString)
adapter.invokeVirtual(Types.PAGE_CONTEXT, TagLoop.GET_QUERY_STRING);