Documentation for method AT-KEY

Documentation for method AT-KEY, assembled from the following types:

language documentation Subscripts

From Subscripts

(Subscripts) method AT-KEY

multi method AT-KEY (::?CLASS:D: $key)

Expected to return the element associated with $key. This is what postcircumfix { } normally calls.

If you want an element to be mutable (like they are for the built-in Hash type), you'll have to make sure to return it in the form of an item container that evaluates to the element's value when read, and updates it when assigned to. (Remember to use return-rw or the is rw routine trait to make that work; see the example.)

On the other hand if you want your collection to be read-only, feel free to return non-container values directly.