Questions tagged [tag-invoke]
4 questions
12
votes
1 answer
Why does tag_invoke pattern need the Niebloid std::tag_invoke at all?
This question assumes familiarity with the customization point management technique tag_invoke, introduced in P1895R0.
A customization point object can be defined according to P1895R0 as:
inline constexpr struct foo_cpo {
// simplified original…
Nick
- 931
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- 17
3
votes
1 answer
customisation point for alias to std types
Let's say I am writing some generic algorithm in lib namespace that calls a customisation point my_func.
First attempt is using ADL for my_func
one of the user wants to specialise my_func for his type, which is an alias to std type. Surely define it…
Hui
- 571
- 1
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1
vote
1 answer
Boost Json conversion error for array of custom object
I'm trying to code a simple json to struct (and back) conversion by using tag_invoke overload of boost::json lib.
Those are my structs:
template
void extract( boost::json::object const& obj, T& t, boost::json::string_view key )
{
t =…
hirish
- 188
- 9
1
vote
1 answer
Class cannot serialize itself using boost::json
I wrote a tiny class which relies on boost::json to serialize itself.
It fails to compile since compiler sounds to fail finding tag_invoke() functions which implement json::value<=>myClass translation :
/usr/include/boost/json/value_from.hpp:87:35:…
sylwa06
- 77
- 10