Iterators

Iterators are special values that are used to step through the items of Str, List and Dict. Creating them from a HIR perspective is as easy as calling .to_iter() on the source expression. Depending on the base collection, the return type of LV2Expr::from(it).next(..) will change:

Str: Characters of the string.
Dict: A List in which the first item is the key and the second item is the value.

Only List causes the iterator to return a contained value as is.

Ranges

You can also use LV2Expr::iter_ranged(from, to) if you want to have a sequence of numbers. Note that from is inclusive and to is exclusive.


#![allow(unused)]
fn main() {
let it1 = LV2Expr::iter_ranged(0, 5);
// => [0, 1, 2, 3, 4]

let it2 = LV2Expr::iter_ranged(-5, 5);
// => [-5, -4, -3, -2, -1, 0, 1, 2, 3, 4]

// passing an iterator expression into `Iter::reverse` does 
// exactly what you would expect

let it3 = LV2Expr::create_ranged(0, 5).reverse();
// => [4, 3, 2, 1, 0]

// you can also omit `from` and `to` by passing a `Nil` value

let it4 = LV2Expr::iter_ranged(Value::Nil, 5)
// => [0, 1, 2, 3, 4]

let it5 = LV2Expr::iter_ranged(10, Value::Nil)
// => [10, 11, 12, ...]
}

Example

If you want to control the iterator more granularly, feel free to use LV2Expr::from(it).has_next() and LV2Expr::from(it).next().


#![allow(unused)]
fn main() {
let (it, item) = &lv2_var!(it, item);

main_hir.assign(it, lv2_list!(1, 2, 3, 4).to_iter());

main_hir
    .repeat_until(LV2Expr::from(it).has_next().not()))
    .assign(item, LV2Expr::from(it).next());
}