w1_2.rs

// A set of small examples that your parser should accept and parse into an ast
// you should also be able to print the ast (debug ":?" or even prettier using display "{}")
//
// Notice that a sequence of statements may have an optional trailing ";"

fn _let_and_return() {
    // a function taking no arguments returning the unit type
    fn a() -> () {
        let _a: i32 = 5; // this returns a unit type
    }

    // a function taking two i32 arguments returning the i32 type
    fn b(_x: i32, _y: i32) -> i32 {
        3 // this returns 3 (as i32)
    }

    // a function taking two i32 arguments returning the i32 type
    // with some let statements
    fn c(x: i32, y: i32) -> i32 {
        let a: i32 = 5;
        let b: i32 = x + y; // this will be an infix operator "+""
        -a - (-b) * y // here we have prefix operator "-"
    }
}

// More advanced statements
fn _if_then_else_and_while() {
    // a function taking two bool arguments returning the bool type
    // with some let statements and function calls
    fn a(x: bool, y: bool) -> bool {
        if x && y {
            let a: bool = true;
            y || a
        } else {
            x && false
        }
    }

    // a function taking two bool arguments returning the i32 type
    // with some let statements and function calls
    fn b(x: bool, y: bool) -> i32 {
        let a: bool = a(x, y || false);
        let mut b: i32 = 0;
        if a && y {
            let a: bool = true; // shadowing
            if y || a {
                b = b + 1;
            };
        } else {
            if !(x && false) {
                b = b - 1;
            }
        };
        b + 3
    }

    // a function taking two bool arguments returning the i32 type
    // while
    fn c(x: bool, y: bool) -> i32 {
        let mut b: i32 = 0;
        let mut c: i32 = 1;
        while (b < 10) {
            c = c * 2;
        }; // added ";" here... to make parsing easier, it is still valid Rust though
        c
    }
}

// optionally you may support other integer types, such as u8, u16, u32, u64, i8, i16, i64 and usize
// you may also support explicit local scopes
//
// later we will introduce references and user defined data types