private boolean evaluateChargeClause(String str) {
		float c = 0;
		try {
			c = Float.valueOf(str).floatValue();
		}
		catch (NumberFormatException e) {
			out(ScriptEvent.FAILED, str + " cannot be parsed as a number.");
			return false;
		}
		int nop = model.getAtomCount();
		if (nop <= 0)
			return true;
		for (int k = 0; k < nop; k++) {
			if (atom[k].isSelected())
				view.setCharge(k, c);
		}
		view.repaint();
		model.notifyChange();
		return true;
	}