amorfo77/json
1
0 Fork 0
mirror of https://github.com/nlohmann/json.git synced 2026-10-13 01:47:11 +00:00
Code Issues Packages Projects Releases Wiki Activity

deploy: 40a62947d3

Browse Source
This commit is contained in:
nlohmann committed 2026-10-12 07:35:31 +00:00
1 parent 79119509a9
commit 22fba27145
555 files changed
+17342 -1394
Download Patch File Download Diff File Expand all files Collapse all files

No files matched your search

api/macros/json_diagnostic_positions.md
+170 -6
View File
@@ -70,13 +70,114 @@ When the macro is not defined, the library will define it to its default value.
??? example "Example: retrieving positions"
```cpp
--8<-- "examples/diagnostic_positions.cpp"
#include <iostream>
#define JSON_DIAGNOSTIC_POSITIONS 1
#include <nlohmann/json.hpp>
using json = nlohmann::json;
int main()
{
std::string json_string = R"(
{
"address": {
"street": "Fake Street",
"housenumber": 1
}
}
)";
json j = json::parse(json_string);
std::cout << "Root diagnostic positions: \n";
std::cout << "\tstart_pos: " << j.start_pos() << '\n';
std::cout << "\tend_pos:" << j.end_pos() << "\n";
std::cout << "Original string: \n";
std::cout << "{\n \"address\": {\n \"street\": \"Fake Street\",\n \"housenumber\": 1\n }\n }" << "\n";
std::cout << "Parsed string: \n";
std::cout << json_string.substr(j.start_pos(), j.end_pos() - j.start_pos()) << "\n\n";
std::cout << "address diagnostic positions: \n";
std::cout << "\tstart_pos:" << j["address"].start_pos() << '\n';
std::cout << "\tend_pos:" << j["address"].end_pos() << "\n\n";
std::cout << "Original string: \n";
std::cout << "{ \"street\": \"Fake Street\",\n \"housenumber\": 1\n }" << "\n";
std::cout << "Parsed string: \n";
std::cout << json_string.substr(j["address"].start_pos(), j["address"].end_pos() - j["address"].start_pos()) << "\n\n";
std::cout << "street diagnostic positions: \n";
std::cout << "\tstart_pos:" << j["address"]["street"].start_pos() << '\n';
std::cout << "\tend_pos:" << j["address"]["street"].end_pos() << "\n\n";
std::cout << "Original string: \n";
std::cout << "\"Fake Street\"" << "\n";
std::cout << "Parsed string: \n";
std::cout << json_string.substr(j["address"]["street"].start_pos(), j["address"]["street"].end_pos() - j["address"]["street"].start_pos()) << "\n\n";
std::cout << "housenumber diagnostic positions: \n";
std::cout << "\tstart_pos:" << j["address"]["housenumber"].start_pos() << '\n';
std::cout << "\tend_pos:" << j["address"]["housenumber"].end_pos() << "\n\n";
std::cout << "Original string: \n";
std::cout << "1" << "\n";
std::cout << "Parsed string: \n";
std::cout << json_string.substr(j["address"]["housenumber"].start_pos(), j["address"]["housenumber"].end_pos() - j["address"]["housenumber"].start_pos()) << "\n\n";
}
```
Output:
```
--8<-- "examples/diagnostic_positions.output"
Root diagnostic positions:
start_pos: 5
end_pos:109
Original string:
{
"address": {
"street": "Fake Street",
"housenumber": 1
}
}
Parsed string:
{
"address": {
"street": "Fake Street",
"housenumber": 1
}
}
address diagnostic positions:
start_pos:26
end_pos:103
Original string:
{ "street": "Fake Street",
"housenumber": 1
}
Parsed string:
{
"street": "Fake Street",
"housenumber": 1
}
street diagnostic positions:
start_pos:50
end_pos:63
Original string:
"Fake Street"
Parsed string:
"Fake Street"
housenumber diagnostic positions:
start_pos:92
end_pos:93
Original string:
1
Parsed string:
1
```
The output shows the start/end positions of all the objects and fields in the JSON string.
@@ -84,13 +185,44 @@ When the macro is not defined, the library will define it to its default value.
??? example "Example: using only diagnostic positions in exceptions"
```cpp
--8<-- "examples/diagnostic_positions_exception.cpp"
#include <iostream>
#define JSON_DIAGNOSTIC_POSITIONS 1
#include <nlohmann/json.hpp>
using json = nlohmann::json;
/* Demonstration of type error exception with diagnostic positions support enabled */
int main()
{
//Invalid json string - housenumber type must be int instead of string
const std::string json_invalid_string = R"(
{
"address": {
"street": "Fake Street",
"housenumber": "1"
}
}
)";
json j = json::parse(json_invalid_string);
try
{
int housenumber = j["address"]["housenumber"];
std::cout << housenumber;
}
catch (const json::exception& e)
{
std::cout << e.what() << '\n';
}
}
```
Output:
```
--8<-- "examples/diagnostic_positions_exception.output"
[json.exception.type_error.302] (bytes 92-95) type must be number, but is string
```
The output shows the exception with start/end positions only.
@@ -98,13 +230,45 @@ When the macro is not defined, the library will define it to its default value.
??? example "Example: using extended diagnostics with positions enabled in exceptions"
```cpp
--8<-- "examples/diagnostics_extended_positions.cpp"
#include <iostream>
#define JSON_DIAGNOSTICS 1
#define JSON_DIAGNOSTIC_POSITIONS 1
#include <nlohmann/json.hpp>
using json = nlohmann::json;
/* Demonstration of type error exception with diagnostic positions support enabled */
int main()
{
//Invalid json string - housenumber type must be int instead of string
const std::string json_invalid_string = R"(
{
"address": {
"street": "Fake Street",
"housenumber": "1"
}
}
)";
json j = json::parse(json_invalid_string);
try
{
int housenumber = j["address"]["housenumber"];
std::cout << housenumber;
}
catch (const json::exception& e)
{
std::cout << e.what() << '\n';
}
}
```
Output:
```
--8<-- "examples/diagnostics_extended_positions.output"
[json.exception.type_error.302] (/address/housenumber) (bytes 92-95) type must be number, but is string
```
The output shows the exception with diagnostic path info and start/end positions.