iteratorlike

Iteratorlike describes objects or interfaces that resemble iterators by providing a controlled way to access elements of a sequence one at a time. Such objects typically expose a method to advance to the next item and a signal to indicate when the sequence is exhausted. They may also offer optional capabilities such as peeking at the next element without consuming it, or resetting to the beginning.

In practice, iteratorlike behavior is implemented in a variety of ways across programming languages. Some languages define formal iterator interfaces, while others rely on duck typing or conventions. For example, Python uses an iterator protocol with __iter__ and __next__, Java relies on hasNext and next, and Rust provides an Iterator trait with a next method. Despite differences in naming, the common theme is a stateful, single-pass progression through a sequence, often with lazy evaluation that computes elements on demand rather than storing them all in memory.

Iteratorlike objects are well suited for streaming data, large or potentially infinite sequences, and pipelines where elements are processed one by one. They enable memory-efficient processing, composability through chaining operations, and backpressure in streaming scenarios. They can be consumable, meaning they advance and lose access to previous elements, though some implementations permit resetting or multiple passes.

Common considerations include the exact API surface, error handling during advancement, and thread-safety. While “iteratorlike” emphasizes similarity to iterators, concrete behavior can vary between languages and libraries. See also: iterable, iterator protocol, stream, cursor.