Predefined Interfaces
Iterator
Predefined Interfaces
PHP Manual

# The Traversable interface

## Introduction

Interface to detect if a class is traversable using foreach.

Abstract base interface that cannot be implemented alone. Instead it must be implemented by either IteratorAggregate or Iterator.

> Note: Internal (built-in) classes that implement this interface can be used in a foreach construct and do not need to implement IteratorAggregate or Iterator.

> Note: This is an internal engine interface which cannot be implemented in PHP scripts. Either IteratorAggregate or Iterator must be used instead.

## Interface synopsis

Traversable
Traversable {
}

This interface has no methods, its only purpose is to be the base interface for all traversable classes.

Predefined Interfaces
Iterator
Predefined Interfaces
PHP Manual