Trait FromBool

Source

pub trait FromBool {
    // Required methods
    fn as_changed_unchanged(self) -> Outcome;
    fn as_changed_continue(self) -> Outcome;
}

Expand description

Experimental

Convert to Outcome from bool.

The problem is that there are two possible combinations

true/false -> Changed/Unchanged
true/false -> Changed/Continue

Which one, depends on the use-case. Do you want the event to be handled finally or do you want to give a parent widget the chance to react to an event unless your widget really does something worth-wile.

This occurs for navigation keys.

Left navigates backwards in your widget.
- When the start is reached the widget is done.
  - There may be a super widget that can do it’s super navigation if it knows that fact. => return Outcome::Changed as long as you change your location and Outcome::Continue otherwise.

For the Changed/Unchanged pair I don’t have a good example, so maybe that was the wrong default anyway. But I can’t change the From<bool> behavior as that would really break things.

Hence, this trait.