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1.8 KiB
1.8 KiB
nlohmann::basic_json::is_primitive
constexpr bool is_primitive() const noexcept;
This function returns #!cpp true if and only if the JSON type is primitive (string, number, boolean, #!json null,
binary).
Return value
#!cpp true if type is primitive (string, number, boolean, #!json null, or binary), #!cpp false otherwise.
Exception safety
No-throw guarantee: this member function never throws exceptions.
Complexity
Constant.
Possible implementation
constexpr bool is_primitive() const noexcept
{
return is_null() || is_string() || is_boolean() || is_number() || is_binary();
}
Notes
The term primitive stems from RFC 8259:
JSON can represent four primitive types (strings, numbers, booleans, and null) and two structured types (objects and arrays).
This library extends primitive types to binary types, because binary types are roughly comparable to strings. Hence,
is_primitive() returns #!cpp true for binary values.
Examples
??? example
The following code exemplifies `is_primitive()` for all JSON types.
```cpp
--8<-- "examples/is_primitive.cpp"
```
Output:
```json
--8<-- "examples/is_primitive.output"
```
See also
- is_structured() returns whether JSON value is structured
- is_null() returns whether JSON value is
null - is_string() returns whether JSON value is a string
- is_boolean() returns whether JSON value is a boolean
- is_number() returns whether JSON value is a number
- is_binary() returns whether JSON value is a binary array
Version history
- Added in version 1.0.0.
- Extended to return
#!cpp truefor binary types in version 3.8.0.