Add data-models stub

Author: dhardy

src/SUMMARY.md

@@ -6,3 +6,4 @@
 - [Sync-counter: Adapt'ing AppData](sync-counter.md)
 - [Calculator: make_widget and grid](calculator.md)
 - [Custom widgets](custom-widget.md)
+- [Data models](data-models.md)

src/data-models.md

@@ -0,0 +1,25 @@
+# Sync-counter: data models
+
+*Topics: data models and view widgets*
+
+TODO:
+
+-   [`ListView`] and [`ListData`]
+-   [`Driver`], including predefined impls
+-   [`Filter`] and [`UnsafeFilteredList`]. This rather messy to use (improvable?). The latter should eventually be replaced with a safe variant.
+-   [`MatrixView`] and [`MatrixData`]. (Will possibly gain support for row/column labels and be renamed `TableView`.)
+
+For now, see the examples:
+
+-   [`examples/ldata-list-view.rs`](https://github.com/kas-gui/kas/blob/master/examples/data-list-view.rs) uses [`ListView`] with custom [`ListData`] and [`Driver`]
+-   [`examples/gallery.rs`](https://github.com/kas-gui/kas/blob/master/examples/gallery.rs#L338)'s `filter_list` uses [`UnsafeFilteredList`] with a custom [`Driver`]. Less code but possibly more complex.
+-   [`examples/times-tables.rs`](https://github.com/kas-gui/kas/blob/master/examples/times-tables.rs) uses [`MatrixView`] with custom [`MatrixData`] and [`driver::NavView`]. Probably the easiest example.
+
+[`ListView`]: https://docs.rs/kas/latest/kas/view/struct.ListView.html
+[`ListData`]: https://docs.rs/kas/latest/kas/view/trait.ListData.html
+[`Driver`]: https://docs.rs/kas/latest/kas/view/trait.Driver.html
+[`driver::NavView`]: https://docs.rs/kas/latest/kas/view/driver/struct.NavView.html
+[`Filter`]: https://docs.rs/kas/latest/kas/view/filter/trait.Filter.html
+[`UnsafeFilteredList`]: https://docs.rs/kas/latest/kas/view/filter/struct.UnsafeFilteredList.html
+[`MatrixView`]: https://docs.rs/kas/latest/kas/view/struct.MatrixView.html
+[`MatrixData`]: https://docs.rs/kas/latest/kas/view/trait.MatrixData.html