std/iter

Iterator utilities for traversing collections.

Struct: Iter<T>

Generic iterator over elements of type T.

struct Iter<T> {
public:
    data: Vector<T>;
    index: uint64;
}

Warning

Iter<T> uses a Vector<T> under the hood and every .next() calls use the Vector<T>.take(i) method, which moves out T then collapses the vector to not have empty holes. It’s very inefficient for long iterator. Iter<T> should be reworked to use [T] under the hood and manage it by itself.

Constructor

import "std/iter";
import "std/vector";

let vec = new Vector<int64>([1, 2, 3]);
let iter = new Iter<int64>(vec);

Copy Constructor

Note

Most copy constructors need T to be copyable, it is not yet properly enforced by the compiler. Currently you will get a weird error akin to “use of moved value” somewhere in the std lib code.

import "std/iter";
import "std/vector";

let vec = new Vector<int64>([1, 2, 3]);
let iter = new Iter<int64>(vec);
let iter_copy = new Iter<int64>(&iter);

Static Methods

Iter<T>::from_array(data: [T]) -> Iter<T>

Create an iterator from an array.

let arr = [1, 2, 3];
let iter = Iter<int64>::from_array(arr);

Iter<char>::from_string(data: String) -> Iter<char>

Create an iterator from a String.

import "std/string";

let str = new String("Hi");
let iter = Iter<char>::from_string(str);

Iter<char>::from_str(data: &const string) -> Iter<char>

Create an iterator from a string primitive.

let text = "Hi";
let iter = Iter<char>::from_str(&text);

Instance Methods

next(&this) -> optional<T>

Get the next item (returns empty if exhausted).

let iter = Iter<int64>::from_array([1, 2]);
let first = iter.next();   // optional::of(1)
let second = iter.next();  // optional::of(2)
let third = iter.next();   // optional::empty()

peek(&this) -> optional<&const T>

Peek at the next item without advancing.

let iter = Iter<int64>::from_array([1, 2]);
let peeked = iter.peek();  // optional::of(&1)
let next = iter.next();     // optional::of(1)

has_next(&this) -> bool

Check if there are more items.

while iter.has_next() {
    let item = iter.next().value();
    println(item);
}