spl抽象语法树的c++实现代码

以下是一个简单的 C++ 实现，实现了基本的 SPL 抽象语法树节点，并提供了一些示例方法：

#include <iostream>
#include <string>
#include <vector>

using namespace std;

// SPL 抽象语法树节点类
class SplAstNode {
public:
    virtual ~SplAstNode() {}
    virtual string getType() const = 0;
    virtual void print() const = 0;
};

// 整数字面量节点类
class IntLiteral : public SplAstNode {
public:
    IntLiteral(int value) : value(value) {}
    virtual string getType() const { return "int"; }
    virtual void print() const { cout << value; }
private:
    int value;
};

// 变量节点类
class Variable : public SplAstNode {
public:
    Variable(const string& name) : name(name) {}
    virtual string getType() const { return "variable"; }
    virtual void print() const { cout << name; }
private:
    string name;
};

// 表达式节点类
class Expression : public SplAstNode {
public:
    virtual string getType() const { return "expression"; }
    virtual void print() const {
        for (auto child : children) {
            child->print();
            cout << " ";
        }
    }
    void addChild(SplAstNode* child) { children.push_back(child); }
private:
    vector<SplAstNode*> children;
};

// 二元运算表达式节点类
class BinaryExpression : public Expression {
public:
    BinaryExpression(const string& op) : op(op) {}
    virtual string getType() const { return "binary_expression"; }
    virtual void print() const {
        children[0]->print();
        cout << " " << op << " ";
        children[1]->print();
    }
private:
    string op;
};

// 声明语句节点类
class DeclarationStatement : public SplAstNode {
public:
    DeclarationStatement(const string& type, const string& name) : type(type), name(name) {}
    virtual string getType() const { return "declaration_statement"; }
    virtual void print() const {
        cout << type << " ";
        cout << name;
    }
private:
    string type;
    string name;
};

// SPL 抽象语法树类
class SplAst {
public:
    SplAst(SplAstNode* root) : root(root) {}
    ~SplAst() { delete root; }
    void print() const { root->print(); }
private:
    SplAstNode* root;
};

int main() {
    // 构造一个抽象语法树
    BinaryExpression* expr = new BinaryExpression("+");
    expr->addChild(new IntLiteral(1));
    expr->addChild(new IntLiteral(2));
    DeclarationStatement* decl = new DeclarationStatement("int", "x");
    Expression* assign_expr = new Expression();
    assign_expr->addChild(new Variable("x"));
    assign_expr->addChild(expr);
    SplAstNode* root = new Expression();
    root->addChild(decl);
    root->addChild(assign_expr);
    SplAst ast(root);

    // 输出语法树
    ast.print();
    cout << endl;

    return 0;
}

这只是一个简单的实现，实际的 SPL 抽象语法树可能要更复杂，具体的实现方式也会因实际需求而异。