use std::builtins::{generic_args_of, tuple_head_of}; use std::util::unit; // Peano integers 0, S(0), S(S(0)), ... struct Zero {} struct Succ {} impl Zero { fn val(_v: Zero) -> i32 { 0 } } impl Succ { fn val(_v: Succ) -> i32 { unit::().val() + 1 } } fn is_zero() -> bool { std::typing::matches::() } type One = Succ; type Two = Succ; type Three = Succ; type Four = Succ; type Five = Succ; type Six = Succ; type Seven = Succ; type Eight = Succ; type Nine = Succ; type Ten = Succ; type Eleven = Succ; type Twelve = Succ; type Not = when is_zero::() { One } else { Zero }; type And = when is_zero::() { Zero } else { B }; type Or = when is_zero::() { B } else { One }; type Xor = when is_zero::() { B } else { Not }; type Prev = when is_zero::() { Zero } else { tuple_head_of> }; type Add = when is_zero::() { A } else { Succ>> }; type Sub = when is_zero::() { A } else { Sub, Prev> }; type Mul = when is_zero::() { Zero } else { Add>> }; type DivT = when is_zero::() { typeof(compile_fail!("division by zero")) } else when is_zero::, B>>() { Idx } else { DivT, B, Succ> }; type Div = DivT; type Mod = Sub, B>>; type Fibonacci = when is_zero::>() { T } else { Add>, Fibonacci>>> }; type IsPrimeT = when std::typing::matches::() { One // = true } else when is_zero::>() { Zero // = false } else { IsPrimeT> }; type IsPrime = when is_zero::>() { Zero // = false } else { IsPrimeT }; type Gcd = when is_zero::() { A } else { Gcd> }; fn main() { println!("Arithmetic:"); println!("10 * 5 + (6 * 2) / 3 = {}", unit::< Add< Mul, Div< Mul, Three > >>() .val()); println!("Fibonacci:"); println!("fib(0) = {}", unit::>().val()); println!("fib(1) = {}", unit::>().val()); println!("fib(2) = {}", unit::>().val()); println!("fib(3) = {}", unit::>().val()); println!("fib(4) = {}", unit::>().val()); println!("fib(5) = {}", unit::>().val()); println!("fib(6) = {}", unit::>().val()); println!("fib(7) = {}", unit::>().val()); println!("fib(8) = {}", unit::>().val()); println!("fib(9) = {}", unit::>().val()); println!("fib(10) = {}", unit::>().val()); println!("fib(11) = {}", unit::>().val()); println!("fib(12) = {}", unit::>().val()); println!("Primality:"); println!("is_prime(1) = {}", unit::>().val()); println!("is_prime(2) = {}", unit::>().val()); println!("is_prime(3) = {}", unit::>().val()); println!("is_prime(4) = {}", unit::>().val()); println!("is_prime(5) = {}", unit::>().val()); println!("is_prime(6) = {}", unit::>().val()); println!("is_prime(7) = {}", unit::>().val()); println!("is_prime(8) = {}", unit::>().val()); println!("is_prime(9) = {}", unit::>().val()); println!("is_prime(10) = {}", unit::>().val()); println!("is_prime(11) = {}", unit::>().val()); println!("is_prime(12) = {}", unit::>().val()); }