The Traversable interface

    (PHP 5, PHP 7, PHP 8)

    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.

    Interface synopsis

    interfaceTraversable {
    }

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

    Changelog

    VersionDescription
    7.4.0 The Traversable interface can now be implemented by abstract classes. Extending classes must implement Iterator or IteratorAggregate.

    Notes

    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:

    Prior to PHP 7.4.0, this internal engine interface couldn't be implemented in PHP scripts. Either IteratorAggregate or Iterator must be used instead.

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