Logical operators

Andy C++ uses the keywords and, or, and not for logical operators. If you are coming from Rust, write and and or instead of && and ||.

let ready = has_input and not failed;
let retry = timed_out or disconnected;

Short-circuiting

and and or are lazy. Andy C++ evaluates the right-hand side only when it needs that value to decide the result.

let x = 0;

true and { x = x + 1; false };
false and { x = x + 1; false };
true or { x = x + 1; false };
false or { x = x + 1; false };

assert_eq(x, 2);

false and ... stops at false, and true or ... stops at true.

Precedence

and binds tighter than or.

let a = true or true and false;  // true
let b = false and true or true;  // true

That means Andy C++ reads those expressions as:

let a = true or (true and false);
let b = (false and true) or true;

Bitwise operators

Boolean values also support the non-lazy operators &, |, and ~.

Use and and or when you want short-circuiting. Use & and | when you need both sides to run.