made for a competition against my cousin where I proved swift's superiority over java :)

basic_calculator.swift

//
//  ContentView.swift
//  utilities
//
//  Created by Aadish Verma on 11/7/24.
//

import SwiftUI
import Foundation
import Expression
typealias Expression = NumericExpression

class Point: Hashable {
    let x: Int
    let y: Int

    init(x: Int, y: Int) {
        self.x = x
        self.y = y
    }

    static func == (lhs: Point, rhs: Point) -> Bool {
        return lhs.x == rhs.x && lhs.y == rhs.y
    }

    func hash(into hasher: inout Hasher) {
        hasher.combine(x)
        hasher.combine(y)
    }
}
// calculator app
func evaluateExpression(expression: String) -> Double? {
    let exp = Expression(expression)
    return try? exp.evaluate()
}
struct ContentView: View {
    @State var currentState = ""
    // grid:
    // Clear * open paren * close paren * divide
    // 7 * 8 * 9 * multiply
    // 4 * 5 * 6 * subtract
    // 1 * 2 * 3 * add
    // 0 * . * delete * equal
    static var actions: [Point: (String, (String) -> String, KeyboardShortcut)] = [
        Point(x: 0,y: 0): ("C", { _ in "" }, KeyboardShortcut(.delete, modifiers: .command)),
        Point(x: 1,y: 0): ("(", { $0 + "(" }, KeyboardShortcut("(", modifiers: [])),
        Point(x: 2,y: 0): (")", { $0 + ")" }, KeyboardShortcut(")", modifiers: [])),
        Point(x: 3,y: 0): ("÷", { $0 + "/" }, KeyboardShortcut("/", modifiers: [])),
        Point(x: 0,y: 1): ("7", { $0 + "7" }, KeyboardShortcut("7", modifiers: [])),
        Point(x: 1,y: 1): ("8", { $0 + "8" }, KeyboardShortcut("8", modifiers: [])),
        Point(x: 2,y: 1): ("9", { $0 + "9" }, KeyboardShortcut("9", modifiers: [])),
        Point(x: 3,y: 1): ("×", { $0 + "*" }, KeyboardShortcut("*", modifiers: [])),
        Point(x: 0,y: 2): ("4", { $0 + "4" }, KeyboardShortcut("4", modifiers: [])),
        Point(x: 1,y: 2): ("5", { $0 + "5" }, KeyboardShortcut("5", modifiers: [])),
        Point(x: 2,y: 2): ("6", { $0 + "6" }, KeyboardShortcut("6", modifiers: [])),
        Point(x: 3,y: 2): ("−", { $0 + "-" }, KeyboardShortcut("-", modifiers: [])),
        Point(x: 0,y: 3): ("1", { $0 + "1" }, KeyboardShortcut("1", modifiers: [])),
        Point(x: 1,y: 3): ("2", { $0 + "2" }, KeyboardShortcut("2", modifiers: [])),
        Point(x: 2,y: 3): ("3", { $0 + "3" }, KeyboardShortcut("3", modifiers: [])),
        Point(x: 3,y: 3): ("+", { $0 + "+" }, KeyboardShortcut("+", modifiers: [])),
        Point(x: 0,y: 4): ("0", { $0 + "0" }, KeyboardShortcut("0", modifiers: [])),
        Point(x: 1,y: 4): (".", { $0 + "." }, KeyboardShortcut(".", modifiers: [])),
        Point(x: 2,y: 4): ("⌫", { String($0.dropLast()) }, KeyboardShortcut(.delete, modifiers: [])),
        Point(x: 3,y: 4): (
            "=",
            { do { return try evaluateExpression(expression: $0)?.description ?? $0} catch { return $0 } },
            KeyboardShortcut(.return, modifiers: [])
        )
    ]
    var body: some View {
        VStack {
            
            TextField("Math the night away", text: $currentState)
                .font(.title.monospacedDigit())
                .multilineTextAlignment(.center)
                .frame(width: 100*4)
                .padding()
            ForEach(0..<6) { ypos in
                HStack { 
                    ForEach(0..<4) {xpos in
                        ZStack {
                            if let (label, action, shortcut) = Self.actions[Point(x: xpos, y: ypos)] {
                                Button(action: {
                                    currentState = action(currentState)
                                }) {
                                    Text(label).padding().font(.title.monospacedDigit())
                                }.keyboardShortcut(shortcut)
                                    .mask(RoundedRectangle(cornerRadius: 10))
                            }
                            else {
                                EmptyView()
                            }
                        }.frame(width: 100, height: 100)
                    }
                }
            }
        }
        //Periodic()
        //MyExperimentalView()
    }
}

#Preview {
    ContentView()
}