panic

Aborts with a message: panic "message".

The message is printed as panic: <message> at <file>:<line>:<col> and the program exits with status 1. The defer blocks of the functions it leaves still run. A panic inside a child task fails that task and its scope instead of the program. Prefer raise or Result for errors a caller can handle.

fn checked_div(int a, int b) -> int {
    if b == 0 {
        panic "division by zero";
    }
    return a / b;
}

See also#

• Result
• fn: Declares a function, a method, or (written in an expression) an anonymous function.
• let: Declares a mutable local variable.
• const: Declares a binding that cannot be reassigned: a local, a module constant, or a class field that is set only by new.
• static: Declares a module-level or class-level slot shared by the whole program, or a method without self.
• readonly: A read-only view of a value: nothing reachable through it can be changed.
• if: Runs a block when a bool condition is true.
• else: Introduces the branch of an if that runs when its condition is false (or its pattern does not match).