<?php

declare(strict_types=1);

namespace App\Engine\Cfnpp\Expression;

/**
 * Token representing a distinct part of an expression.
 *
 * @author Adam Pippin <hello@adampippin.ca>
 */
abstract class Token
{
	/**
	 * Check whether the stream passed in contains a valid token of this
	 * type.
	 *
	 * @param  string $stream
	 * @return bool
	 */
	abstract public static function isToken(string $stream): bool;

	/**
	 * Consume a token from the stream.
	 *
	 * Only valid if isToken is true.
	 *
	 * @param  string $stream
	 * @return Token
	 */
	abstract public static function getToken(string &$stream): Token;
}