Iterators

You can enumerate items in any container using an iterator. Iterators are created using the iter built-in function or by using the range keyword.

>>> my_set := {1,2,3}
{1, 2, 3}
>>> iter(my_set)
set_iter({1, 2, 3})

Unlike in Go, the range keyword is available outside of for loop definitions:

>>> range {one: 1, two: 2}
map_iter({"one": 1, "two": 2})

Iterators offer a next method to retrieve the next entry in the sequence. Each entry is returned as an iter_entry object, which has key and value attributes. When the iterator is exhausted, nil is returned instead.

For loops recognize when they're working with iterators and automatically assign each key and value to the loop variables:

>>> s := "abc"
"abc"
>>> for i, c := range s { print("index:", i, "rune:", c) }
index: 0 rune: a
index: 1 rune: b
index: 2 rune: c

Iterators can be used directly as well:

>>> s := "abc"
"abc"
>>> iterator := iter(s)
string_iter("abc")
>>> item := iterator.next()
iter_entry(0, "a")
>>> item.key
0
>>> item.value
"a"