Files
json/docs/mkdocs/docs/examples/view_mode.cpp
T
Niels Lohmann 266432ea65 json_view: view_mode enum instead of bool Editable, node_kind for node::kind
basic_json_document and basic_json_view take a view_mode (read_only, the
default, or editable) instead of a bool: basic_json_document<json, true>
did not say what true means. The shortcut aliases are unchanged.

The kind of a node is a node_kind (the value_t values plus link, 10 as
before), which removes the static_cast<std::uint8_t>(value_t::...) of
every comparison. The node and image layouts are unchanged.

Signed-off-by: Niels Lohmann <mail@nlohmann.me>
2026-10-25 20:41:47 +01:00

30 lines
992 B
C++

#include <iostream>
#include <nlohmann/json_view.hpp>
using nlohmann::basic_json_view;
using nlohmann::view_mode;
// accepts the views of read-only and of editable documents, of json and of ordered_json
template<typename BasicJsonType, view_mode Mode>
std::size_t count_members(basic_json_view<BasicJsonType, Mode> v)
{
return v.is_object() ? v.size() : 0;
}
// accepts only the views of editable documents
template<typename BasicJsonType>
bool is_edited(basic_json_view<BasicJsonType, view_mode::editable> v)
{
return v.is_string() && v.get_string() == "edited";
}
int main()
{
const nlohmann::json_document doc = nlohmann::json_document::parse(R"({"a": 1, "b": 2})");
nlohmann::json_editable_document edoc = nlohmann::json_editable_document::parse(R"({"a": 1})");
edoc.set(edoc.root()["a"], "edited");
std::cout << count_members(doc.root()) << ' ' << count_members(edoc.root()) << '\n';
std::cout << std::boolalpha << is_edited(edoc.root()["a"]) << '\n';
}