Function adapton::catalog::collections::filter_list_of_tree

pub fn filter_list_of_tree<Lev: Level, X: Hash + Clone + 'static, L: ListIntro<X> + ListElim<X> + 'static, T: TreeElim<Lev, X> + 'static>(
    tree: T, 
    pred: Box<Fn(&X) -> bool>
) -> L

Filter the leaf elements of a tree using a user-provided predicate, pred. Returns a list of the elements for which the predicate returns true. Retains exactly one name between any two elements that, in the original sequence, were separated by a name. Does not insert names that were not present in the original sequence.