value::set_at_pointer
Set an element via JSON Pointer.
Synopsis
value*
set_at_pointer(
string_view sv,
value_ref ref,
boost::system::error_code& ec,
set_pointer_options const& opts = {}); (1)
value*
set_at_pointer(
string_view sv,
value_ref ref,
std::error_code& ec,
set_pointer_options const& opts = {}); (2)
value&
set_at_pointer(
string_view sv,
value_ref ref,
set_pointer_options const& opts = {}); (3)Description
This function is used to insert or assign to a potentially nested element of the value using a JSON Pointer string. The function may create intermediate elements corresponding to pointer segments.
The particular conditions when and what kind of intermediate element is created is governed by the ptr parameter.
Each pointer token is considered in sequence. For each token
-
if the containing value is an
object, then a newnullelement is created with key equal to unescaped token string; otherwise -
if the containing value is an
array, and the token represents a past-the-end marker, then anullelement is appended to the array; otherwise -
if the containing value is an
array, and the token represents a number, then if the difference between the number and array’s size is smaller thanopts.max_created_elements, then the size of the array is increased, so that the number can reference an element in the array; otherwise -
if the containing value is of different
kindandopts.replace_any_scalaristrue, or the value isnull, then-
if
opts.create_arraysistrueand the token either represents past-the-end marker or a number, then the value is replaced with an empty array and the token is considered again; otherwise -
if
opts.create_objectsistrue, then the value is replaced with an empty object and the token is considered again; otherwise
-
-
an error is produced.
Complexity
Linear in the sum of size of ptr, size of underlying array, object, or string and opts.max_created_elements.
Exception Safety
Basic guarantee. Calls to memory_resource::allocate may throw.
Return Value
Pointer to the element identified by ptr.
Return Value
Pointer to the element identified by ptr.
Return Value
Reference to the element identified by ptr.
Parameters
| Name | Description |
|---|---|
|
JSON Pointer string. |
|
The value to assign to pointed element. |
|
Set to the error, if any occurred. |
|
The options for the algorithm. |