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| Shelves: the currently selected item | |||||
| Prerequisite Concepts | |||||
Whenever a shelf item is referenced without explicitly selecting an item (with a ^ (key), @ (item) or lastmost indexer), the currently selected item is used.
Initially, the currently selected item on a shelf is always the last item on the shelf. (If the shelf has no items, then there is no currently selected item.)
The currently selected item can be changed by a repeat over loop, a using prefix, or a function call.
There are three cases where a shelf has no current item:
using has established a current item using a @ (item) indexer, and the shelf does not currently have that item (e.g,. when the current item and all items following it have been removed)
using has established a current item using a ^ (key) indexer, and the shelf does not currently have an item with that key value (for example, when the item with that key has been removed, or its key has been removed or changed)
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Prerequisite Concepts Arrays |
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