Feature Description

Slicing is well known from other languages, to get a specific range of items of a list. For example in Python:

my_data = ["foo", "bar", "hello", "world"]
first_half = my_data[:2]
second_half = my_data[2:]
middle = my_data[1:3]

It would be awesome if this was possible in Slint too. An example use-case could be a tab bar where only the first N elements are shown as tabs and the rest is moved into a context menu. Or a notification area where only the first N messages are visible and the rest are collapsed or so. For those use-cases it would actually be great if the slices can be made of dynamic properties, not just hardcoded numbers. E.g.:

property <[string]> my-data: ["foo", "bar", "hello", "world"];
property <int> visible-elements: min(my-data.length, root.height / 20px);

MyListView {
    model: my-data[:visible-elements];
}

MyCollapsible {
    MyListView {
        model: my-data[visible-elements:];
    }
}

Related to #1328 because basically it is a filter model, but the specialized syntax would be much more convenient than a .filter() call for this basic use-case.

Product Impact

Not critical at all, just would have been convenient a few times.