cfnpp/app/Cfnpp/Expression/TokenVariable.php

<?php

declare(strict_types=1);

namespace App\Cfnpp\Expression;

/**
 * Expression token referencing a variable.
 *
 * @author Adam Pippin <hello@adampippin.ca>
 */
class TokenVariable extends Token
{
	/**
	 * Name of the variable this token references.
	 * @var string
	 */
	protected $name;

	/**
	 * Create a new variable token.
	 *
	 * @param string $name
	 */
	public function __construct(string $name)
	{
		$this->name = $name;
	}

	/**
	 * Get the name of the variable this token references.
	 *
	 * @return string
	 */
	public function getName(): string
	{
		return $this->name;
	}

	/**
	 * Determine whether a variable name token can be parsed from a stream.
	 *
	 * @param  string $stream
	 * @return bool
	 */
	public static function isToken(string $stream): bool
	{
		return (bool)preg_match('/^[A-Za-z]$/', $stream[0]);
	}

	/**
	 * Parse a variable token from a stream.
	 *
	 * Returns token, and modifies stream to remove all consumed characters.
	 *
	 * @param  string $stream
	 * @return Token
	 */
	public static function getToken(string &$stream): Token
	{
		$buffer = '';
		$buffer = $stream[0];
		for ($i = 1; $i < strlen($stream); $i++)
		{
			if (preg_match('/^[A-Za-z0-9]$/', $stream[$i]))
			{
				$buffer .= $stream[$i];
			}
			else
			{
				break;
			}
		}

		$stream = substr($stream, strlen($buffer));

		return new TokenVariable($buffer);
	}
}