Abstract supertype of objects which associate values
with keys. Correspondence does not satisfy Category,
since in some cases—List, for example—it is
convenient to consider the subtype a Category of its
values, and in other cases—Map, for example—it
is convenient to treat the subtype as a Category of its
entries.
The item corresponding to a given key may be obtained
from a Correspondence using the item operator:
value bg = settings["backgroundColor"] else white;
The item() operation and item operator result in an
optional type, to reflect the possibility that there is
no item for the given key.
| Attributes | |
| keys | Source Code shared default Category keys The See also: defines |
| Inherited Attributes |
| Attributes inherited from: Object |
| Methods | |
| defines | Source Code Determines if there is a value defined for the given key. See also: definesAny, definesEvery, keys |
| definesAny | Source Code Determines if this See also: defines |
| definesEvery | Source Code Determines if this See also: defines |
| item | Source Code shared formal Item? item(Key key) Returns the value defined for the given key, or
See also: items |
| items | Source Code shared default Item?[] items(Key... keys) Returns the items defined for the given keys, in the same order as the corresponding keys. See also: item |
| Inherited Methods |
| Methods inherited from: Object |