public function isValue() : bool
    {
        return
        $this->type === self::TOKEN_STRING ||
        $this->type === self::TOKEN_NUMBER ||
        $this->type === self::TOKEN_NULL ||
        $this->type === self::TOKEN_BOOL_TRUE ||
        $this->type === self::TOKEN_BOOL_FALSE;
    }
public function isValue() : bool
    {
        return
        $this->type === self::TOKEN_STRING ||
        $this->type === self::TOKEN_NUMBER ||
        $this->type === self::TOKEN_NULL ||
        $this->type === self::TOKEN_BOOL_TRUE ||
        $this->type === self::TOKEN_BOOL_FALSE;
    }
public function isValue ( ) : bool { return $ this -> type === self :: TOKEN_STRING || $ this -> type === self :: TOKEN_NUMBER || $ this -> type === self :: TOKEN_NULL || $ this -> type === self :: TOKEN_BOOL_TRUE || $ this -> type === self :: TOKEN_BOOL_FALSE ; }
Is this a value token?

@return bool
Is this a value token?