Function adapton::catalog::collections::list_filter_lazy

pub fn list_filter_lazy<X: 'static, Le: 'static + ListElim<X>, Li: 'static + ListIntro<X>, F: 'static>(
    l: Le, 
    body: Rc<F>
) -> Li where
    F: Fn(&X) -> bool, 

Lazily filters the list, guided by names in input list. Creates lazy named thunks in output for each name in input.