Re: [boost] Heterogeneous Container Library (HCL) Feedback and Testing

3 Jun 2015


      On Wed, Jun 3, 2015 at 2:42 PM, Andrzej Krzemienski 
wrote:
...
Could you provide some sketch of a real life scenario? The examples show
how I can use it, but I fail to imagine why I would need it. You mentioned
storing the results of various DB queries, how would you make use of data
stored in such way?
Reards,
&rzej
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I put together a simple example below.  I have used a querying library that
returns results in a similar fashion.

// Define some classes
class Paper {//...};
class Notepad {//...};
class Folder {//...};
class Trash {//...};
class Cookie {//...};
class Candy {//...};
class Stapler {//...};
class Coin {//...};

class database
{
    public:
        enum class OBJECT_TYPES { PAPER, NOTEPAD, FOLDER, TRASH, COOKIE,
CANDY, STAPLER, COIN };

        bool peek()
        {
           return index >= data.size() ? false : true;
        }

        OBJECT_TYPES type(size_t column)
        {
           return types_[column];
        }

        template<typename T>
        T* next()
        {
           return static_cast( data[index++] );
        }

    private:
        std::vector types_;
        std::vector data;
        size_t index;
};

using drawer = std::vectorboost::any;

bool add_object( drawer& D, database& db )
{
    if ( !db.peek() ) return false;

    switch ( db.type() )
    {
        case database::OBJECT_TYPES::PAPER:
           D.push_back( db.next<Paper>() );
           break;

       case database::OBJECT_TYPES::NOTEPAD:
           D.push_back( db.next<Notepad>() );
           break;

       case database::OBJECT_TYPES::FOLDER:
           D.push_back( db.next<Folder>() );
           break;

       // continue for all OBJECT_TYPES
    }

    return true;
}


int main()
{
    std::vector<drawer> cabinet;
    size_t num_drawers = 3;
    cabinet.resize(num_drawers);

    std::vector<database> db;
    db.resize(num_drawers);
    // connect to remote database and run query

    // pull results from database
    for (size_t d=0; d

Re: [boost] Heterogeneous Container Library (HCL) Feedback and Testing

James Armstrong