Provide a type that represents the JSON null
value.
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Detailed Description
- Outline
-
-
- Purpose:
- Provide a type that represents the JSON
null
value.
-
- Classes:
-
- See also:
- Component bdljsn_json
-
- Description:
- This component provides a single value-semantic type,
bdljsn::JsonNull
, that can represent the JSON null
value. This provides a degenerate (extremely limited) set of the conventional functionality. Objects of this class can be:
-
default constructed
-
printed ("null" is output)
-
compared with each other (always equal).
- Significantly, there is no way to specify or change the state of these objects. Thus, each object always has the same value as the others.
- Additionally, support is provided for hashing via the
hashAppend
free function and also a swap
function.
-
- Usage:
- In this section we show intended usage of this component.
-
- Example 1: Basic Syntax:
- The scenario below illustrates almost all of the supported operations on the
bdljsn::JsonNull
type:
- First, we create a
bdljsn::JsonNull
object: Then, we examine the object's printed representation: Next, we create a second object of that class and confirm that it equals the object created above. Finally, we confirm that swapping the two objects has no effect. swap(a, b);
assert(a == b);