Struct Io 

pub struct Io {
    pub value: Value,
    pub returned: Value,
}

The built capability, plus the one thing about it a runner has to recognize.

Fields

value: Value

The IO module instance — what __main is applied to, and the whole of what the program is authorized to do.

returned: Value

The iota IO.Proc.return raises with. Io::run compares an uncaught raise against it to tell “the program asked to exit with a status” from “the program failed”; nothing else can mint this value.

Implementations

impl Io

pub fn run(&self, instance: &Value, ctx: &Ctx) -> Run

Run instance’s __main: evaluate the body in the module’s own environment, apply the result to IO, and say how it ended.

pub fn finish(&self, result: Result<Value, Raised>) -> Run

Say how a computation that was given IO ended. run uses it for __main; a host that hands IO to something else, such as the playground’s bare expression, uses it directly.