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61 lines
1.4 KiB
Markdown
61 lines
1.4 KiB
Markdown
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# basic_json::is_primitive
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```cpp
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constexpr bool is_primitive() const noexcept;
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```
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This function returns `#!cpp true` if and only if the JSON type is primitive (string, number, boolean, `#!json null`,
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binary).
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## Return value
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`#!cpp true` if type is primitive (string, number, boolean, `#!json null`, or binary), `#!cpp false` otherwise.
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## Exception safety
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No-throw guarantee: this member function never throws exceptions.
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## Complexity
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Constant.
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## Possible implementation
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```cpp
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constexpr bool is_primitive() const noexcept
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{
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return is_null() || is_string() || is_boolean() || is_number() || is_binary();
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}
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```
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## Notes
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The term *primitive* stems from [RFC 8259](https://tools.ietf.org/html/rfc8259):
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> JSON can represent four primitive types (strings, numbers, booleans, and null) and two structured types (objects and
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> arrays).
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This library extends primitive types to binary types, because binary types are roughly comparable to strings. Hence,
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`is_primitive()` returns `#!cpp true` for binary values.
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## Example
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??? example
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The following code exemplifies `is_primitive()` for all JSON types.
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```cpp
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--8<-- "examples/is_primitive.cpp"
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```
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Output:
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```json
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--8<-- "examples/is_primitive.output"
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```
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## Version history
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- Added in version 1.0.0.
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- Extended to return `#!cpp true` for binary types in version 3.8.0.
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