value = new ConstInteger((Integer) word);
} else if (word instanceof Double) {
value = new ConstDouble((Double) word);
} else if ("true".equals(word) || "yes".equals(word)
|| "on".equals(word)) {
value = new TrueCheck();
} else if ("false".equals(word) || "no".equals(word)
|| "off".equals(word)) {
value = new FalseCheck();
} else if ("null".equals(word)) {
value = new NullExpression();