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//! Demonstrates that you can have a View in a static global variable.
//!
//! This works even when the View is accessed by multiple threads, because
//! it synchronizes internally.
use std::sync::atomic::AtomicUsize;
use std::sync::atomic::Ordering::Relaxed;
use std::thread::{self, sleep};
use std::time::Duration;
// Note: The initial model must also be `const`, so you cannot call `Default::default()`.
// Note: Similarly, you can call `nutmeg::Options::new()` but not `Options::default()`.
static VIEW: nutmeg::View<Model> = nutmeg::View::new(
Model {
i: AtomicUsize::new(0),
},
nutmeg::Options::new(),
);
#[derive(Default)]
struct Model {
i: AtomicUsize,
}
impl nutmeg::Model for Model {
fn render(&mut self, _width: usize) -> String {
format!("i={}", self.i.load(Relaxed))
}
}
fn main() -> std::io::Result<()> {
thread::scope(|scope| {
for tid in 0..3 {
scope.spawn(move || {
VIEW.message(format!("thread {} starting\n", tid));
for _i in 0..20 {
VIEW.update(|model| model.i.fetch_add(1, Relaxed));
sleep(Duration::from_millis(rand::random::<u64>() % 200));
}
VIEW.message(format!("thread {} done\n", tid));
});
}
});
Ok(())
}
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