c++设计模式--解释器模式


解释器模式（Interpreter）定义了一个类体系，用于实现一个小型语言的解释器。它与组合模式很相似，而且常常利用组合模式来实现语法树的构建。

GOOD：通常当一个语言需要解释执行，并且你可以将该语言中的句子表示成为一个抽象的语法树时，可以使用解释器模式。



RES:http://hi.baidu.com/xuehuo_0411/item/41778e77d47f9d43ef1e53e8

C++实现：

[cpp]
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#include <iostream>

#include <vector>

#include <string>

using namespace std;



class Context

{

public:

string input;

string output;

};



class AbstractExpression

{

public:

virtual void Interpret(Context* context) = 0;

};



class Expression : public AbstractExpression

{

public:

virtual void Interpret(Context* context) { cout << "终端解释器" << endl; }

};



class NonTerminalExpression : public AbstractExpression

{

public:

virtual void Interpret(Context* context) { cout << "非终端解释器" << endl; }

};



int main(int argc, char* argv[])

{

Context* context = new Context();

vector<AbstractExpression*> express;

express.push_back(new Expression());

express.push_back(new NonTerminalExpression());

express.push_back(new NonTerminalExpression());



vector<AbstractExpression*>::iterator it;

for (it=express.begin(); it!=express.end(); ++it)

{

(*it)->Interpret(context);

}



return 0;

}

#include <iostream>

#include <vector>

#include <string>

using namespace std;

 

class Context

{

public:

string input;

string output;

};

 

class AbstractExpression

{

public:

virtual void Interpret(Context* context) = 0;

};

 

class Expression : public AbstractExpression

{

public:

virtual void Interpret(Context* context) { cout << "终端解释器" << endl; }

};

 

class NonTerminalExpression : public AbstractExpression

{

public:

virtual void Interpret(Context* context) { cout << "非终端解释器" << endl; }

};

 

int main(int argc, char* argv[])

{

Context* context = new Context();

vector<AbstractExpression*> express;

express.push_back(new Expression());

express.push_back(new NonTerminalExpression());

express.push_back(new NonTerminalExpression());

vector<AbstractExpression*>::iterator it;

for (it=express.begin(); it!=express.end(); ++it)

{

(*it)->Interpret(context);

}

return 0;

}