Re: [Boost-users] Possible Boost.Variant issue with JSON AST

Subject: Re: [Boost-users] Possible Boost.Variant issue with JSON AST
From: Larry Evans (cppljevans_at_[hidden])
Date: 2019-01-11 02:42:55

On 1/10/19 5:36 PM, Michael Powell via Boost-users wrote:
> On Thu, Jan 10, 2019 at 6:15 PM Gavin Lambert via Boost-users
> <boost-users_at_[hidden]> wrote:
>>
>> On 11/01/2019 07:36, Michael Powell wrote:
>>> Here's my attempt at a flattened single source example:
>>>
>>> https://wandbox.org/permlink/83c3VXZ4W1DHoEBc
>>
>> The problems in that code are that you're using completely the wrong types.
> 
> Fair observations. I've updated a bit, which I think is now tracking
> with my local progress. Chiefly now, issues with "incompatible
> skipper"?
> 
> https://wandbox.org/permlink/4spQR8yXweIcVfdB
> 
> Perhaps a repeated tuple issue of some sort? Otherwise, I'm not sure I
> see what's going on there...
> 
> I'd also tried forward declared structs to capture Member, Object,
> Array, etc, but this was running into Boost.Variant incomplete type
> issues.
> 
Try altering what's forward declared:

         struct member_t;

         using members_t = std::vector<member_t>;

         // JSON_PARSER_OBJECT_HPP
         struct object_t {
             members_t members;
             object_t();
             object_t(const object_t& other);
             virtual ~object_t();
         };

         struct value_t
         : boost::variant
           < null_t, boolean_t, str_t
           , floating_point_number_t
           , integer_number_t, object_t, array_t
           >
           {...};

That way, since sizeof(vector<anything>) is known,  sizeof(object_t) is
known.

HTH.

-regards,
Larry