cacao/examples/calculator/calculator.rs
2022-07-15 16:13:27 +02:00

104 lines
2.8 KiB
Rust

use std::sync::{Arc, RwLock};
use cacao::lazy_static::lazy_static;
use cacao::appkit::App;
use crate::CalculatorApp;
#[derive(Clone, Debug)]
pub enum Msg {
Push(i32),
Add,
Subtract,
Multiply,
Divide,
Decimal,
Clear,
Mod,
Invert,
Equals
}
/// Asynchronously calls back through to the top of the application
/// on the main thread.
pub fn dispatch(msg: Msg) {
println!("Dispatching UI message: {:?}", msg);
CALCULATOR.run(msg)
}
lazy_static! {
pub static ref CALCULATOR: Calculator = Calculator::new();
}
#[derive(Debug)]
pub struct Calculator(Arc<RwLock<Vec<String>>>);
impl Calculator {
pub fn new() -> Self {
Calculator(Arc::new(RwLock::new(Vec::new())))
}
pub fn run(&self, message: Msg) {
let mut expression = self.0.write().unwrap();
match message {
Msg::Push(i) => {
// Realistically you might want to check decimal length here or something.
// We're not bothering for this example.
(*expression).push(i.to_string());
let display = (*expression).join("").split(" ").last().unwrap_or("0").to_string();
App::<CalculatorApp, String>::dispatch_main(display);
},
Msg::Decimal => {
let display = (*expression).join("").split(" ").last().unwrap_or("0").to_string();
if !display.contains(".") {
(*expression).push(".".to_string());
App::<CalculatorApp, String>::dispatch_main(display + ".");
}
},
Msg::Add => {
if let Some(last_entry) = (*expression).last() {
if !last_entry.ends_with(" ") {
(*expression).push(" + ".to_string());
}
}
},
Msg::Subtract => {
(*expression).push(" - ".to_string());
},
Msg::Multiply => {
(*expression).push(" * ".to_string());
},
Msg::Divide => {
(*expression).push(" / ".to_string());
},
Msg::Clear => {
(*expression) = Vec::new();
App::<CalculatorApp, String>::dispatch_main("0".to_string())
},
Msg::Equals => {
let mut expr = (*expression).join("");
if expr.ends_with(" ") {
expr.truncate(expr.len() - 3);
}
println!("Expr: {}", expr);
match eval::eval(&expr) {
Ok(val) => { App::<CalculatorApp, String>::dispatch_main(val.to_string()); },
Err(e) => { eprintln!("Error parsing expression: {:?}", e); }
}
}
_ => {}
}
}
}