在C中用不同的结构表示节点类型的AST

#include <stdio.h>
#include <stdlib.h>

// 定义节点类型枚举
typedef enum {
    NODE_TYPE_EXPRESSION,
    NODE_TYPE_STATEMENT,
    NODE_TYPE_DECLARATION
} NodeType;

// 定义表达式节点结构
typedef struct ExpressionNode {
    NodeType type;
    int value; // 示例：假设表达式节点存储一个整数值
} ExpressionNode;

// 定义语句节点结构
typedef struct StatementNode {
    NodeType type;
    char *text; // 示例：假设语句节点存储一个字符串表示的语句
} StatementNode;

// 定义声明节点结构
typedef struct DeclarationNode {
    NodeType type;
    char *identifier; // 示例：假设声明节点存储一个标识符
} DeclarationNode;

// 创建表达式节点
ExpressionNode* createExpressionNode(int value) {
    ExpressionNode *node = (ExpressionNode*)malloc(sizeof(ExpressionNode));
    node->type = NODE_TYPE_EXPRESSION;
    node->value = value;
    return node;
}

// 创建语句节点
StatementNode* createStatementNode(const char *text) {
    StatementNode *node = (StatementNode*)malloc(sizeof(StatementNode));
    node->type = NODE_TYPE_STATEMENT;
    node->text = strdup(text);
    return node;
}

// 创建声明节点
DeclarationNode* createDeclarationNode(const char *identifier) {
    DeclarationNode *node = (DeclarationNode*)malloc(sizeof(DeclarationNode));
    node->type = NODE_TYPE_DECLARATION;
    node->identifier = strdup(identifier);
    return node;
}

// 打印节点信息
void printNode(void *node) {
    switch (((struct Node*)node)->type) {
        case NODE_TYPE_EXPRESSION:
            printf("Expression Node: %d\n", ((ExpressionNode*)node)->value);
            break;
        case NODE_TYPE_STATEMENT:
            printf("Statement Node: %s\n", ((StatementNode*)node)->text);
            break;
        case NODE_TYPE_DECLARATION:
            printf("Declaration Node: %s\n", ((DeclarationNode*)node)->identifier);
            break;
        default:
            printf("Unknown Node Type\n");
            break;
    }
}

int main() {
    ExpressionNode *exprNode = createExpressionNode(10);
    StatementNode *stmtNode = createStatementNode("if (x > 0) { x = x - 1; }");
    DeclarationNode *declNode = createDeclarationNode("int x");

    printNode(exprNode);
    printNode(stmtNode);
    printNode(declNode);

    free(exprNode);
    free(stmtNode->text);
    free(stmtNode);
    free(declNode->identifier);
    free(declNode);

    return 0;
}