import nars.language.SetInt; //导入依赖的package包/类
/**
 * Top-level method that parse a Term in general, which may recursively call
 * itself.
 * <p>
 * There are 5 valid cases: 1. (Op, A1, ..., An) is a CompoundTerm if Op is
 * a built-in operator 2. {A1, ..., An} is an SetExt; 3. [A1, ..., An] is an
 * SetInt; 4. <T1 Re T2> is a Statement (including higher-order Statement);
 * 5. otherwise it is a simple term.
 *
 * @param s0 the String to be parsed
 * @param memory Reference to the memory
 * @return the Term generated from the String
 */
public static Term parseTerm(String s0, Memory memory) throws InvalidInputException {
    String s = s0.trim();
    try {
        if (s.length() == 0) {
            throw new InvalidInputException("missing content");
        }
        Term t = memory.nameToListedTerm(s);    // existing constant or operator
        if (t != null) {
            return t;
        }                           // existing Term
        int index = s.length() - 1;
        char first = s.charAt(0);
        char last = s.charAt(index);
        switch (first) {
            case COMPOUND_TERM_OPENER:
                if (last == COMPOUND_TERM_CLOSER) {
                    return parseCompoundTerm(s.substring(1, index), memory);
                } else {
                    throw new InvalidInputException("missing CompoundTerm closer");
                }
            case SET_EXT_OPENER:
                if (last == SET_EXT_CLOSER) {
                    return SetExt.make(parseArguments(s.substring(1, index) + ARGUMENT_SEPARATOR, memory), memory);
                } else {
                    throw new InvalidInputException("missing ExtensionSet closer");
                }
            case SET_INT_OPENER:
                if (last == SET_INT_CLOSER) {
                    return SetInt.make(parseArguments(s.substring(1, index) + ARGUMENT_SEPARATOR, memory), memory);
                } else {
                    throw new InvalidInputException("missing IntensionSet closer");
                }
            case STATEMENT_OPENER:
                if (last == STATEMENT_CLOSER) {
                    return parseStatement(s.substring(1, index), memory);
                } else {
                    throw new InvalidInputException("missing Statement closer");
                }
            default:
                return parseAtomicTerm(s);
        }
        
    } catch (InvalidInputException e) {
        throw new InvalidInputException(" !!! INVALID INPUT: parseTerm: " + s + " --- " + e.getMessage());
    }

}