code: void removeExistingGlue() {
  		for (int i = outputStream.size() - 1; i >= 0; i--) {
  			RTObject c = outputStream.get(i);
  			if (c instanceof Glue) {
  				outputStream.remove(i);
  			} else if (c instanceof ControlCommand) { // e.g.
  														// BeginString
  				break;
  			}
  		}
  
  		outputStreamDirty();
  	}
docs: Only called when non-whitespace is appended