function reRegExp() {
	return /^\/((?:\\\/|[^\/])+)\/([imgy]*)$/; // eslint-disable-line no-useless-escape
}
Returns a regular expression to parse a regular expression string.

@returns {RegExp} regular expression

@example
var RE_REGEXP = reRegExp();

var bool = RE_REGEXP.test( '/^beep$/' );
// returns true

bool = RE_REGEXP.test( '' );
// returns false