◆ json_pointer()

template<template< typename U, typename V, typename... Args > class ObjectType = std::map, template< typename U, typename... Args > class ArrayType = std::vector, class StringType = std::string, class BooleanType = bool, class NumberIntegerType = std::int64_t, class NumberUnsignedType = std::uint64_t, class NumberFloatType = double, template< typename U > class AllocatorType = std::allocator, template< typename T, typename SFINAE=void > class JSONSerializer = adl_serializer>

nlohmann::basic_json::json_pointer::json_pointer ( const std::string & s = "" )

inlineexplicit

Create a JSON pointer according to the syntax described in Section 3 of RFC6901.

Parameters

[in] s string representing the JSON pointer; if omitted, the empty string is assumed which references the whole JSON value

Exceptions

parse_error.107	if the given JSON pointer s is nonempty and does not begin with a slash (`/`); see example below
parse_error.108	if a tilde (`~`) in the given JSON pointer s is not followed by `0` (representing `~`) or `1` (representing `/`); see example below

Example

The example shows the construction several valid JSON pointers as well as the exceptional behavior.

 #include "json.hpp"
 
 using json = nlohmann::json;
 
 int main()
 {
     // correct JSON pointers
     json::json_pointer p1;
     json::json_pointer p2("");
     json::json_pointer p3("/");
     json::json_pointer p4("//");
     json::json_pointer p5("/foo/bar");
     json::json_pointer p6("/foo/bar/-");
     json::json_pointer p7("/foo/~0");
     json::json_pointer p8("/foo/~1");
 
     // error: JSON pointer does not begin with a slash
     try
     {
         json::json_pointer p9("foo");
     }
     catch (json::parse_error& e)
     {
         std::cout << e.what() << '\n';
     }
 
     // error: JSON pointer uses escape symbol ~ not followed by 0 or 1
     try
     {
         json::json_pointer p10("/foo/~");
     }
     catch (json::parse_error& e)
     {
         std::cout << e.what() << '\n';
     }
 
     // error: JSON pointer uses escape symbol ~ not followed by 0 or 1
     try
     {
         json::json_pointer p11("/foo/~3");
     }
     catch (json::parse_error& e)
     {
         std::cout << e.what() << '\n';
     }
 }

Output (play with this example online):

[json.exception.parse_error.107] parse error at 1: JSON pointer must be empty or begin with '/' - was: 'foo'
[json.exception.parse_error.108] parse error: escape character '~' must be followed with '0' or '1'
[json.exception.parse_error.108] parse error: escape character '~' must be followed with '0' or '1'

The example code above can be translated with

g++ -std=c++11 -Isrc doc/examples/json_pointer.cpp -o json_pointer

Since: version 2.0.0

Definition at line 12577 of file json.hpp.