Struct NavStack 

pub struct NavStack<T> { /* private fields */ }

A generic navigation history. T names a view (an app’s route/screen descriptor). Back and forward keep browser-style history; pushing after a Back clears the abandoned forward branch.

Implementations

impl<T> NavStack<T>

where T: Clone + PartialEq,

pub fn new(root: T) -> NavStack<T>

A stack rooted at root (the first, un-poppable view).

pub fn current(&self) -> &T

The view currently on screen (the top of the stack).

pub fn push(&mut self, view: T)

Push view as the new current view. A push equal to the current view is a no-op (navigating to where you already are does not grow history), so repeated identical navigations don’t stack up and Back stays meaningful.

pub fn replace_current(&mut self, view: T)

Replace the current view in place without growing history. Use when a view mutates into a variant of itself (e.g. a query refining) that a Back should skip over rather than replay.

pub fn can_go_back(&self) -> bool

pub fn can_go_forward(&self) -> bool

pub fn back(&mut self) -> Option<&T>

Pop the current view and return a reference to the view now on screen, or None when already at the root (nothing to pop).

pub fn forward(&mut self) -> Option<&T>

Move forward after a Back, or return None at the newest entry.

pub fn apply(&mut self, action: NavAction) -> Option<&T>

Apply a NavAction, returning the view now on screen if it changed.

pub fn depth(&self) -> usize

Number of views in the history (>= 1).

pub fn reset(&mut self, root: T)

pub fn past(&self) -> &[T]

Entries older than the current view, oldest first.

pub fn future(&self) -> &[T]

Entries reachable with Forward, nearest entry last.

pub fn from_parts(past: Vec<T>, current: T, future: Vec<T>) -> NavStack<T>

Rebuild a stack from an exported history. past is oldest first and future is nearest-first, matching past and future.

Trait Implementations

impl<T> Clone for NavStack<T>

where T: Clone,

fn clone(&self) -> NavStack<T>

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl<T> Debug for NavStack<T>

where T: Debug,

fn fmt(&self, f: &mut Formatter<'_>) -> Result<(), Error>

Formats the value using the given formatter.

impl<T> PartialEq for NavStack<T>

where T: PartialEq,

fn eq(&self, other: &NavStack<T>) -> bool

Tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl<T> Eq for NavStack<T>

where T: Eq,

impl<T> StructuralPartialEq for NavStack<T>