| # basic_json::is_primitive |
| |
| ```cpp |
| 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 |
| |
| ```cpp |
| 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](https://tools.ietf.org/html/rfc8259): |
| |
| > 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. |
| |
| ## Example |
| |
| ??? example |
| |
| The following code exemplifies `is_primitive()` for all JSON types. |
| |
| ```cpp |
| --8<-- "examples/is_primitive.cpp" |
| ``` |
| |
| Output: |
| |
| ```json |
| --8<-- "examples/is_primitive.output" |
| ``` |
| |
| ## Version history |
| |
| - Added in version 1.0.0. |
| - Extended to return `#!cpp true` for binary types in version 3.8.0. |