119 lines
4.0 KiB
Rust
119 lines
4.0 KiB
Rust
//! Useful, foundational hooks that 3rd parties can implement.
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//! Currently implemented:
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//! - [x] use_ref
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//! - [x] use_state
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//! - [ ] use_reducer
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//! - [ ] use_effect
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pub use use_ref_def::use_ref;
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pub use use_state_def::use_state;
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mod use_state_def {
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use crate::innerlude::*;
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use std::{cell::RefCell, ops::DerefMut, rc::Rc};
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struct UseState<T: 'static> {
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new_val: Rc<RefCell<Option<T>>>,
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current_val: T,
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caller: Box<dyn Fn(T) + 'static>,
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}
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/// Store state between component renders!
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/// When called, this hook retrives a stored value and provides a setter to update that value.
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/// When the setter is called, the component is re-ran with the new value.
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///
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/// This is behaves almost exactly the same way as React's "use_state".
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///
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/// Usage:
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/// ```ignore
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/// static Example: FC<()> = |ctx| {
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/// let (counter, set_counter) = use_state(ctx, || 0);
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/// let increment = || set_couter(counter + 1);
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/// let decrement = || set_couter(counter + 1);
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///
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/// html! {
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/// <div>
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/// <h1>"Counter: {counter}" </h1>
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/// <button onclick={increment}> "Increment" </button>
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/// <button onclick={decrement}> "Decrement" </button>
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/// </div>
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/// }
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/// }
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/// ```
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pub fn use_state<'a, T: 'static, F: FnOnce() -> T + 'static>(
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ctx: &'_ Context<'a>,
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initial_state_fn: F,
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) -> (&'a T, &'a impl Fn(T)) {
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ctx.use_hook(
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move || UseState {
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new_val: Rc::new(RefCell::new(None)),
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current_val: initial_state_fn(),
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caller: Box::new(|_| println!("setter called!")),
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},
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move |hook| {
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let inner = hook.new_val.clone();
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let scheduled_update = ctx.schedule_update();
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// get ownership of the new val and replace the current with the new
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// -> as_ref -> borrow_mut -> deref_mut -> take
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// -> rc -> &RefCell -> RefMut -> &Option<T> -> T
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if let Some(new_val) = hook.new_val.as_ref().borrow_mut().deref_mut().take() {
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hook.current_val = new_val;
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}
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// todo: swap out the caller with a subscription call and an internal update
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hook.caller = Box::new(move |new_val| {
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// update the setter with the new value
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let mut new_inner = inner.as_ref().borrow_mut();
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*new_inner = Some(new_val);
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// Ensure the component gets updated
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scheduled_update();
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});
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// box gets derefed into a ref which is then taken as ref with the hook
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(&hook.current_val, &hook.caller)
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},
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|_| {},
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)
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}
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}
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mod use_ref_def {
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use crate::innerlude::*;
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use std::{cell::RefCell, ops::DerefMut};
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pub struct UseRef<T: 'static> {
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_current: RefCell<T>,
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}
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impl<T: 'static> UseRef<T> {
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fn new(val: T) -> Self {
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Self {
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_current: RefCell::new(val),
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}
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}
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fn modify(&self, modifier: impl FnOnce(&mut T)) {
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let mut val = self._current.borrow_mut();
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let val_as_ref = val.deref_mut();
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modifier(val_as_ref);
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}
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pub fn current(&self) -> std::cell::Ref<'_, T> {
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self._current.borrow()
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}
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}
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/// Store a mutable value between renders!
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/// To read the value, borrow the ref.
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/// To change it, use modify.
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/// Modifications to this value do not cause updates to the component
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/// Attach to inner context reference, so context can be consumed
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pub fn use_ref<'a, T: 'static>(
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ctx: &'_ Context<'a>,
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initial_state_fn: impl FnOnce() -> T + 'static,
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) -> &'a UseRef<T> {
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ctx.use_hook(|| UseRef::new(initial_state_fn()), |state| &*state, |_| {})
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}
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}
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