Boost property_tree 用于存储指针
是否可以在 boost 属性树中存储指向对象的指针，然后使用迭代器来检索数据？我正在尝试执行类似的操作：
property_tree::ptree pt;
pt.put<CGUICrateElement*>("1.2.3.4", new MyObject() );
//... more tree construction here...
然后递归地迭代所有树节点，例如：
property_tree::ptree::iterator iter = treeNode.begin();
property_tree::ptree::iterator iter_end = treeNode.end();
for ( ; iter != iter_end; ++iter )
{
MyObject *obj = lexical_cast<MyObject*>(iter->second.data());
//... etc
问题是我收到错误 lexical_cast.hpp:1112: error: no match for 'operator>>'在“流>>”中词法转换行上的输出'。
并将以下内容添加到 MyObject 并没有帮助
friend std::istream& operator>>(std::istream& in, MyObject& obj){ return in; }
我也尝试了 c 强制转换和动态强制转换，但无济于事。
在 ptree 中是否可以使用指针？我即将创建自己的树结构作为解决方法，我想我会先在这里问。
干杯。
Is it possible to store pointers to objects in boost property trees, and then use an iterator to retrieve the data? I'm trying to do something like:
property_tree::ptree pt;
pt.put<CGUICrateElement*>("1.2.3.4", new MyObject() );
//... more tree construction here...
and then recursively itererate through all the tree nodes with something like:
property_tree::ptree::iterator iter = treeNode.begin();
property_tree::ptree::iterator iter_end = treeNode.end();
for ( ; iter != iter_end; ++iter )
{
MyObject *obj = lexical_cast<MyObject*>(iter->second.data());
//... etc
The problem is I get the error lexical_cast.hpp:1112: error: no match for 'operator>>' in 'stream >> output' on the lexical cast line.
and adding the following to MyObject doesn't help
friend std::istream& operator>>(std::istream& in, MyObject& obj){ return in; }
I've also tried c casts and dynamic casts to no avail.
Is using pointers even possible inside a ptree? I'm about to just create my own tree structure as a workaround by I figured I'd ask here first.
Cheers.
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添加运算符>>当您实际尝试 lexical_cast 到 MyObject 的指针时，对 MyObject 的引用将无济于事。您可以想象创建一个
operator>>(std::istream&, MyObject*&)。但是，请记住，property_tree 是为从文本文件读取配置而设计的，因此您将享受在对象与文本之间进行转换的乐趣。不要使用 property_tree 作为通用数据结构。在内部它将期望处理文本。
Adding an operator>> for a reference to MyObject won't help when you're actually trying to lexical_cast to a pointer to MyObject. You could conceivably create an
operator>>(std::istream&, MyObject*&). However, remember that property_tree is designed for reading configuration from text files, so you'll have the joy of converting your object to and from text.Don't use property_tree as a generic data structure. Internally it will be expecting to deal with text.
它看起来很像您想要一个序列化解决方案。我在这篇文章中介绍了一些基础知识（包括通过指针存储）：
使用指针复制并重新填充结构体实例
此示例还显示了 XML 的序列化，以及包含（可能）重复指针的集合。反序列化时，指针将被忠实地重建（包括重复）。
It is looking a lot like you wanted a serialization solution. I covered some ground (including storing through pointers) in this post:
copying and repopulating a struct instance with pointers
This example also shows serialization to XML, collections containing (potentially) duplicated pointers. On deserialization, the pointers will be reconstructed faithfully (including the duplication).