yield

Suspends a generator and hands a value to the code that resumed it.

yield v produces v as the result of the resume. Used as an expression (let msg = yield v;) it also receives the value sent with resume h with x. yield from other() delegates to another coroutine.

gen fn echo() {
    let msg = yield "ready";
    yield msg;
}

fn main() {
    let h = echo();
    let first = resume h; // "ready"
    let second = resume h with "hello"; // "hello"
}

See also#

• 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).
• while: Repeats a block while a bool condition is true.