public static function instance() : NumberSyntax
    {
        if (self::$instance === null)
            self::$instance = new NumberSyntax;
        return self::$instance;
    }
public static function instance() : NumberSyntax
    {
        if (self::$instance === null)
            self::$instance = new NumberSyntax;
        return self::$instance;
    }
public static function instance ( ) : NumberSyntax { if ( self :: $ instance === null ) self :: $ instance = new NumberSyntax ; return self :: $ instance ; }
Returns the NumberSyntax instance.

@return Tarsana\Syntax\NumberSyntax
Returns the NumberSyntax instance .