Enum magnus::block::Yield

pub enum Yield<I> {
    Iter(I),
    Enumerator(Enumerator),
}

Helper type for functions that either yield a single value to a block or return an Enumerator.

I must implement Iterator<Item = T>, where T implements IntoValue.

Examples

use magnus::{
    block::{block_given, Yield},
    define_global_function, eval, method,
    prelude::*,
    rb_assert, RArray, Value,
};

fn count_to_3(rb_self: Value) -> Yield<impl Iterator<Item = u8>> {
    if block_given() {
        Yield::Iter(1..=3)
    } else {
        Yield::Enumerator(rb_self.enumeratorize("count_to_3", ()))
    }
}

define_global_function("count_to_3", method!(count_to_3, 0));

// call Ruby method with a block.
let a = RArray::new();
rb_assert!("count_to_3 {|i| a << i} == nil", a);
rb_assert!("a == [1, 2, 3]", a);

// call Ruby method without a block.
let enumerator: Value = eval("count_to_3").unwrap();

rb_assert!("enumerator.next == 1", enumerator);
rb_assert!("enumerator.next == 2", enumerator);

Variants

Iter(I)

Yields I::Item to given block.

Enumerator(Enumerator)

Returns Enumerator from the method.