repose_core/lib.rs
1//! # State, Signals, and Effects
2//!
3//! Repose uses a small reactive core instead of an explicit widget tree with
4//! mutable fields. There are three main pieces:
5//!
6//! - `Signal<T>` - observable, reactive value.
7//! - `remember*` - lifecycle‑aware storage bound to composition.
8//! - `effect` / `scoped_effect` - side‑effects with cleanup.
9//!
10//! ## Signals
11//!
12//! `Signal<T>` is a cloneable handle to a piece of state:
13//!
14//! ```rust
15//! use repose_core::*;
16//!
17//! let count = signal(0);
18//! count.set(1);
19//! count.update(|v| *v += 1);
20//! assert_eq!(count.get(), 2);
21//! ```
22//!
23//! Reads participate in a dependency graph: when you call `get()` inside an
24//! observer or `produce_state`, future writes will automatically recompute that
25//! observer.
26//!
27//! ## Remembered state
28//!
29//! UI state is typically held in `remember_*` slots rather than globals:
30//!
31//! ```ignore
32//! use repose_core::*;
33//!
34//! fn CounterView() -> View {
35//! let count = remember_state(|| 0); // Rc<RefCell<i32>>
36//!
37//! let on_click = {
38//! let count = count.clone();
39//! move || *count.borrow_mut() += 1
40//! };
41//!
42//! repose_ui::Button(
43//! format!("Count = {}", *count.borrow()),
44//! on_click,
45//! )
46//! }
47//! ```
48//!
49//! - `remember` and `remember_state` are order‑based: the Nth call in a
50//! composition slot always refers to the Nth stored value.
51//! - `remember_with_key` and `remember_state_with_key` are key‑based and more
52//! stable across conditional branches.
53//!
54//! ## Derived state
55//!
56//! `produce_state` computes a `Signal<T>` from other signals and recomputes it
57//! automatically when dependencies change:
58//!
59//! ```rust
60//! use repose_core::*;
61//!
62//! let first = signal("Jane".to_string());
63//! let last = signal("Doe".to_string());
64//!
65//! let full = produce_state("full_name", {
66//! let first = first.clone();
67//! let last = last.clone();
68//! move || format!("{} {}", first.get(), last.get())
69//! });
70//!
71//! assert_eq!(full.get(), "Jane Doe");
72//! ```
73//!
74//! ## Effects and cleanup
75//!
76//! Use `effect` / `scoped_effect` for one‑off side‑effects with cleanups:
77//!
78//! ```ignore
79//! use repose_core::*;
80//!
81//! fn Example() -> View {
82//! scoped_effect(|| {
83//! log::info!("Mounted Example");
84//! on_unmount(|| log::info!("Unmounted Example"))
85//! });
86//!
87//! // ...
88//! repose_ui::Box(Modifier::new())
89//! }
90//! ```
91//!
92//! - `effect` runs once when the view is composed and returns a `Dispose`
93//! guard that will be run when the scope is torn down.
94//! - `scoped_effect` is wired to the current `Scope` and is cleaned up on
95//! scope disposal (e.g. when a navigation entry is popped).
96//!
97//! For long‑running tasks (network, timers), prefer building small helpers on
98//! top of `scoped_effect` so everything cleans up correctly when the UI that
99//! owns it disappears.
100
101pub mod animation;
102pub mod animation_driver;
103pub mod clipboard;
104pub mod color;
105pub mod cursor;
106pub mod dnd;
107pub mod effects;
108pub mod effects_ext;
109pub mod indication;
110pub mod error;
111pub mod focus;
112pub mod frame_clock;
113pub mod geometry;
114pub mod input;
115pub mod locals;
116pub mod modifier;
117pub mod prelude;
118pub mod reactive;
119pub mod render_api;
120pub mod runtime;
121pub mod scope;
122pub mod scope_cache;
123pub mod semantics;
124pub mod shortcuts;
125pub mod signal;
126pub mod state;
127pub mod tests;
128pub mod text;
129pub mod view;
130
131pub use color::*;
132pub use cursor::*;
133pub use indication::*;
134pub use dnd::*;
135pub use effects::*;
136pub use effects_ext::*;
137pub use focus::*;
138pub use frame_clock::{
139 peek_frame_request, request_frame, signal_fired, take_frame_request, take_signal_fired,
140};
141pub use geometry::*;
142pub use locals::*;
143pub use modifier::*;
144pub use prelude::*;
145pub use reactive::*;
146pub use render_api::*;
147pub use runtime::*;
148pub use runtime::{FocusDirection, FocusManager, FocusRequester, take_focus_request};
149pub use semantics::*;
150pub use signal::*;
151pub use state::*;
152pub use text::*;
153pub use view::*;
154
155pub use repose_macros::View;
156
157/// Memoized composition scope with input + signal tracking.
158///
159/// Wraps a composable block, caching its output as long as:
160/// 1. The explicit inputs are unchanged (by `Hash` comparison).
161/// 2. No signal read during body execution has been written since last run.
162///
163/// When the cache is hit, the body is NOT executed — the previously-composed
164/// View is returned instead, with proper ID and composer cursor advancement
165/// to keep sibling scopes consistent.
166///
167/// # Usage
168///
169/// ```ignore
170/// use repose_core::*;
171///
172/// fn MyView(s: &mut Scheduler, title: &str, count: i32) -> View {
173/// scope!("my_view", s, [title, count], {
174/// Column(Modifier::new()).child((
175/// Text(title),
176/// Text(format!("Count: {count}")),
177/// ))
178/// })
179/// }
180/// ```
181///
182/// # Signal auto-tracking
183///
184/// Any `Signal::get()` call inside the body automatically registers the scope
185/// as a dependency. When that signal is written, the scope is marked dirty and
186/// recomposed on the next frame. You don't need to put signal values in the
187/// input list — the reactive system handles dependencies implicitly.
188///
189/// ```ignore
190/// let size = signal(100.0);
191/// scope!("animated", s, [], {
192/// let cur = size.get(); // auto-tracked; cache invalidated on write
193/// Box(Modifier::new().size(cur, cur))
194/// })
195/// ```
196///
197/// # `f32`/`f64` in explicit inputs
198///
199/// Float types don't implement `Hash`. For float inputs, use `.to_bits()`:
200///
201/// ```ignore
202/// scope!("s", s, [my_float.to_bits()], { ... })
203/// ```
204///
205/// Or — better — read floats from a `Signal<f32>` inside the body (auto-tracked).
206///
207/// # Compatibility with `remember`
208///
209/// `remember` slots consumed inside the body are tracked and properly advanced
210/// on cache hit, so sibling `remember` calls remain consistent.
211#[macro_export]
212macro_rules! scope {
213 // With explicit inputs
214 ($key:expr, $s:expr, [$($input:expr),+ $(,)?], $body:block) => {{
215 let _key: &str = $key;
216
217 let _input_hash = {
218 use std::hash::{Hash, Hasher};
219 let mut _hasher = std::collections::hash_map::DefaultHasher::new();
220 $(
221 Hash::hash(&$input, &mut _hasher);
222 )*
223 _hasher.finish()
224 };
225
226 if !$crate::scope_cache::should_run(_key, _input_hash) {
227 $crate::scope_cache::get_cached(_key, $s)
228 } else {
229 $crate::scope_cache::clear_scope_deps(_key);
230
231 let _prev_cursor = $crate::runtime::COMPOSER.with(|c| c.borrow().cursor);
232
233 $s.enter_scope(_key);
234 let mut _result = $crate::scope_cache::with_scope_key(_key, || $body);
235 $s.exit_scope();
236
237 _result.modifier.repaint_boundary = true;
238 _result.scope_key = Some(_key.to_string());
239
240 let _slot_delta = $crate::runtime::COMPOSER.with(|c| c.borrow().cursor) - _prev_cursor;
241
242 $crate::scope_cache::set_cache(_key, _input_hash, _result.clone(), _slot_delta);
243
244 _result
245 }
246 }};
247
248 // Without explicit inputs — skip Hash import
249 ($key:expr, $s:expr, [], $body:block) => {{
250 let _key: &str = $key;
251 let _input_hash: u64 = 0;
252
253 if !$crate::scope_cache::should_run(_key, _input_hash) {
254 $crate::scope_cache::get_cached(_key, $s)
255 } else {
256 $crate::scope_cache::clear_scope_deps(_key);
257
258 let _prev_cursor = $crate::runtime::COMPOSER.with(|c| c.borrow().cursor);
259
260 $s.enter_scope(_key);
261 let mut _result = $crate::scope_cache::with_scope_key(_key, || $body);
262 $s.exit_scope();
263
264 _result.modifier.repaint_boundary = true;
265 _result.scope_key = Some(_key.to_string());
266
267 let _slot_delta = $crate::runtime::COMPOSER.with(|c| c.borrow().cursor) - _prev_cursor;
268
269 $crate::scope_cache::set_cache(_key, _input_hash, _result.clone(), _slot_delta);
270
271 _result
272 }
273 }};
274}