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Function map_w_default

Source 
pub fn map_w_default<S, F>(s: S, f: F) -> Map<S, F, ConstTrue>
where
    S: Borrowable<Borrowed: HibitTree<DefaultData: IsConstTrue>>,
    for<'a, 'b> F: UnaryFunction<<S::Borrowed as HibitTreeTypes<'a>>::Data> + UnaryFunction<<S::Borrowed as HibitTreeTypes<'a>>::DataUnchecked> + UnaryFunction<<S::Borrowed as HibitTreeTypes<'a>>::DataOrDefault> + UnaryFunction<<<S::Borrowed as HibitTreeTypes<'a>>::Cursor as HibitTreeCursorTypes<'b>>::Data> + UnaryFunction<<<S::Borrowed as HibitTreeTypes<'a>>::Cursor as HibitTreeCursorTypes<'b>>::DataUnchecked> + UnaryFunction<<<S::Borrowed as HibitTreeTypes<'a>>::Cursor as HibitTreeCursorTypes<'b>>::DataOrDefault>,
Expand description

Same as map, but allows access to data_or_default methods.

§Map function

Your function MUST preserve the default value when it appears as input. You’re allowed to change its type, but it must be semantically default value. Like &0 -> 0, (&0, &0) -> 0, 0 -> None, etc.