toString method
A string representation of this object.
Some classes have a default textual representation,
often paired with a static parse
function (like int.parse).
These classes will provide the textual representation as
their string representation.
Other classes have no meaningful textual representation
that a program will care about.
Such classes will typically override toString
to provide
useful information when inspecting the object,
mainly for debugging or logging.
Implementation
@override
String toString() {
if (hasKey) {
return key!.isNotEmpty ? '?:$key' : '?:';
} else if (hasIndex) {
return index! >= 0 ? '?#$index' : '?#';
} else {
return '?';
}
}