提高property_tree:在模板类上,每个键具有多个值 [英] Boost property_tree: multiple values per key, on a template class
问题描述
关于此主题,提高property_tree:每个键有多个值提出了一种读取升压树的多重密钥的方法。我将在下面粘贴修改后的版本
On this topic, Boost property_tree: multiple values per key, a method is proposed to read multiples keys of a boost tree. I will paste a modified version below
template<int dim>
struct my_vector
{
std::vector<double> a_vector;
};
译者将是:
template<int dim>
struct my_vector_translator
{
typedef std::string internal_type;
typedef my_vector external_type;
// Get a my_vector from a string
boost::optional<external_type> get_value(const internal_type& str)
{
if (!str.empty())
{
std::vector val;
val.resize(dim)
std::stringstream s(str);
double temp;
for (int i=0, i < dim; ++i){
s >> temp;
val.a_vector[i] = temp;
return boost::optional<external_type>(val);
}
else
return boost::optional<external_type>(boost::none);
}
};
现在,我应该如何正确注册翻译?
And now, how should i do to register the translator properly ?
namespace boost { namespace property_tree
{
template<typename Ch, typename Traits, typename Alloc>
struct translator_between<std::basic_string< Ch, Traits, Alloc >, my_vector<it want something here of course, where do i get it from ?> >
{
typedef my_vector_translator<it want something here of course, where do i get it from ?> type;
};
} }
在添加了前面的代码之后,可以将property_tree用作:
After you include the previous code, you can use property_tree as:
pt.get<my_vector ??and here where do i put the size ?>("box.x");
以某种方式,我觉得类my_vector没用。我不能直接使用std :: vector吗?
And somehow i feel that the class my_vector is useless. Couldn't I work directly with std::vector ?
我想要类似的东西:
pt.get<std::vector<double>, 3>("mesh.a_line_where_i_know_i_have_3_doubles_to_read");
谢谢。
推荐答案
在我看来,大小已经是 my_vector
类模板的模板参数。
It seems to me that size is already the template argument to the my_vector
class template.
所以
pt.get<my_vector<3> >("box.x");
应该不错
部分专业化可以引入额外的模板参数,因此只需在列表中添加 size_t N
:
A partial specialization can introduce extra template arguments, so just add size_t N
to the list:
namespace boost { namespace property_tree {
template<typename Ch, typename Traits, typename Alloc, size_t N>
struct translator_between<std::basic_string<Ch, Traits, Alloc>, my_vector<N> >
{
typedef my_vector_translator<N> type;
};
} }
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