undef is used to express values that do not exists, or which have no valid path. The value
undef occurs whenever a carbon
is queried for a non-existing path using a dot path expression.
|absence of data (structure-defined)||0||none|
Carbon File snippet
[ [N] ]
undef does not match to a Json
null, use a Carbon
null type instead. For more, see Section Nulls.
Since there is no mapping from a Carbon
undef value to a Json value for Json-formatted output, a
undef value is formatted as a Json-string prefixed with
Json File snippet
Note that this is a uni-directed mapping from Carbon files to Json files. The opposite direction, i.e., mapping from
undef, is not defined.
undef values are not supported for column containers.