解释器模式Demo

#include <QCoreApplication>
#include <iostream>
#include <cstring>
#include <unordered_set>
#include <numeric>
#include <vector>
#include <unordered_set>

class Expression
{
public:
    virtual bool Interpret(std::string mess) = 0;
};

class TerminaExpression : public Expression
{
public:
    TerminaExpression(std::vector<std::string> info)
    {
        foreach (auto &e, info)
        {
            m_set.insert(e);
            qDebug() << m_set.size() << Qt::endl;
        }
    }

    bool Interpret(std::string mess) override
    {
        for(const auto &e : m_set)
        {
            qDebug() << "pos1 : " << QString::fromUtf8(e.c_str()) << Qt::endl;
        }

        auto got = m_set.find(mess);
        if(got == m_set.end())
        {
            qDebug() << "查无此人 或 学校" << Qt::endl;
            return false;
        }
        else
        {
            qDebug() << "找到了" << QString::fromUtf8((*got).c_str()) << Qt::endl;
            return true;
        }
    }
private:
    std::unordered_set<std::string> m_set;
};

class AndExpression : public Expression
{
public:
    AndExpression(Expression *school, Expression *student)
    {
        m_school = school;
        m_student  = student;
    }

    std::vector<std::string> split(std::string s, std::string seprate)
    {
        std::vector<std::string> ret;
        int seprate_len  = seprate.length();
        int start = 0;
        int index;
        while((index = s.find(seprate, start)) != -1)
        {
            ret.push_back(s.substr(start, index - start));
            start = index + seprate_len;
        }

        if(start < s.length())
            ret.push_back(s.substr(start, s.length() - start));
        return ret;
    }

    bool Interpret(std::string mess)
    {
        std::vector<std::string> s = split(mess, "的");
        qDebug() << "s[0]: " << QString::fromUtf8(s[0].c_str()) << ", s[1]: " << QString::fromUtf8(s[1].c_str()) << Qt::endl;
        return m_school->Interpret(s[0]) && m_student -> Interpret(s[1]);
    }

private:
    Expression *m_school;
    Expression *m_student;
};

class Context
{
public:
    Context()
    {
        Expression *school = new TerminaExpression(schools);
        Expression *student = new TerminaExpression(students);
        schoolStudent = new AndExpression(school, student);
    }

    void enterCan(std::string mess)
    {
        bool ok = schoolStudent->Interpret(mess);
        if(ok)
            qDebug() << "这个学生是 "  << QString::fromUtf8(mess.c_str()) << "可以进入校园!" << Qt::endl;
        else
            qDebug() << QString::fromUtf8(mess.c_str()) << "不可以进入校园!" << Qt::endl;
    }

private:
    std::vector<std::string> schools = {"QH", "BD"};
    std::vector<std::string> students = {"明明", "红红", "蓝蓝"};
    Expression *schoolStudent;
};


int main(int argc, char *argv[])
{
    QCoreApplication a(argc, argv);
    Context *per = new Context();
    per->enterCan("QH的明明");
    per->enterCan("BD的东东");
    delete per;

    return a.exec();
}