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use crossterm::event::{self, Event, KeyCode, KeyEvent, KeyModifiers};
use std::io;
use tui::{
backend::Backend,
layout::{Constraint, Direction, Layout},
widgets::{List, ListItem, Paragraph},
Frame, Terminal,
};
use pfc::{ui, Operator};
enum Signal {
None,
Exit,
}
#[derive(Default)]
struct App {
stack: Vec<f64>,
input_buffer: String,
}
impl App {
fn handle_input(&mut self, key: KeyEvent) -> Signal {
match key.modifiers {
KeyModifiers::CONTROL => match key.code {
KeyCode::Char('c') => {
return Signal::Exit;
}
_ => {}
},
KeyModifiers::NONE => match key.code {
KeyCode::Char('q') => {
return Signal::Exit;
}
KeyCode::Char(c) => {
if c.is_ascii_digit() {
self.input_buffer.push(c);
} else if c == '.' && !self.input_buffer.contains('.') {
if self.input_buffer.len() == 0 {
self.input_buffer.push('0');
}
self.input_buffer.push(c);
} else if let Ok(op) = Operator::parse(c) {
if self.input_buffer.len() > 0 {
self.stack.push(self.input_buffer.parse::<f64>().unwrap());
self.input_buffer = String::new();
}
self.perform_operation(op);
}
}
KeyCode::Enter => {
self.stack.push(self.input_buffer.parse::<f64>().unwrap());
self.input_buffer = String::new();
}
KeyCode::Backspace => {
self.input_buffer.pop();
}
_ => {}
},
_ => {}
}
return Signal::None;
}
fn draw<B: Backend>(&self, f: &mut Frame<B>) {
let chunks = Layout::default()
.direction(Direction::Vertical)
.constraints([Constraint::Length(1), Constraint::Percentage(100)].as_ref())
.split(f.size());
f.render_widget(Paragraph::new(self.input_buffer.as_str()), chunks[0]);
let items: Vec<ListItem> = (self.stack)
.iter()
.rev()
.map(|f| ListItem::new(format!("{}", f)))
.collect();
f.render_widget(List::new(items), chunks[1]);
}
fn perform_operation(&mut self, op: Operator) {
let rhs = match self.stack.pop() {
Some(f) => f,
None => {
return;
}
};
let lhs = match self.stack.pop() {
Some(f) => f,
None => {
return;
}
};
match op {
Operator::Add => self.stack.push(lhs + rhs),
Operator::Sub => self.stack.push(lhs - rhs),
Operator::Mul => self.stack.push(lhs * rhs),
Operator::Div => self.stack.push(lhs / rhs),
}
}
}
fn main() -> io::Result<()> {
let app = App::default();
let mut terminal = ui::init_terminal()?;
let result = run(app, &mut terminal);
ui::cleanup_terminal(terminal)?;
result
}
fn run<B: Backend>(mut app: App, terminal: &mut Terminal<B>) -> io::Result<()> {
loop {
terminal.draw(|f| app.draw(f))?;
if let Event::Key(key) = event::read()? {
if let Signal::Exit = app.handle_input(key) {
return Ok(());
}
}
}
}
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