s9e / RegexpBuilder

	* @param  string $expr

	* @return bool

	*/

	protected function exprIsChar($expr)

	{

		$regexps = [

			// Escaped literal or escape sequence such as \w but not \R

			'(^\\\\[adefhnrstvwDHNSVW\\W]$)D',

			// Unicode properties such as \pL or \p{Lu}

			'(^\\\\p(?:.|\\{[^}]+\\})$)Di',

			// An escape sequence such as \x1F or \x{2600}

			'(^\\\\x(?:[0-9a-f]{2}|\\{[^}]+\\})$)Di'

		];

		foreach ($regexps as $regexp)

		{

			if (preg_match($regexp, $expr))

			{

				return true;

			}

		}

		return false;

	}

	/**

	* Test whether given expression is quantifiable

	* @param  string $expr

	* @return bool

	*/

	protected function exprIsQuantifiable($expr)

	{

		$regexps = [

			// A dot or \R

			'(^(?:\\.|\\\\R)$)D',

			// A character class

			'(^\\[\\^?(?:([^\\\\\\]]|\\\\.)(?:-(?-1))?)++\\]$)D'

		];

		foreach ($regexps as $regexp)

		{

			if (preg_match($regexp, $expr))

			{

				return true;

			}

		}

		return $this->exprIsChar($expr);

	}

}