How can I create a table in an .hpp for a general contract? (Using the CDT)

Question

THE STRUCTURE OF MY PROJECT

I am working in mycontract.cpp, which imports myheader.hpp

---

WHAT I WANT

I want to create a table in myheader.hpp, for a generic contract, "IN THEORY" as follows:

struct [[eosio::table, eosio::contract(_self)]] test {
  ...
}

---

WHAT IS NOT WORKING

1. eosio::contract(_self), in the WHAT I WANT section, is not a valid code.
2. in what used to be the standard way of defining a table, the table section in the ABI is not generated by the new compiler eosio-cpp.

In fact, if I create a table like the following:

struct [[eosio::table]] test {
  ...
}

the code compiles; but, the table does not appear in mycontract's tables section in the ABI.

---

WHAT IS WORKING

If I create a table in myheader.hpp, for a specific contract, as follows:

struct [[eosio::table, eosio::contract("mycontract")]] test {
  ...
}

the code compiles; and, the table appears in mycontract's table section in the ABI.

Answer 1

It really depends on what you are going to achieve.

If you are just trying to reuse the old code in a hurry, I would suggest:

SOLUTION 1

header.hpp

struct [[ eosio::table]] test {
  uint64_t prim_key;
  uint64_t timestamp;

  auto primary_key() const { return prim_key; }
};

one.cpp

#include <eosiolib/asset.hpp>
#include <eosiolib/eosio.hpp>

using namespace eosio;

CONTRACT one : public contract {
private:
  #include "../header.hpp"
  typedef multi_index<name("one"), test> test_table;

public:
  using contract::contract;
  ACTION hi(name user) { print_f("Hello % from one", user); }
};

EOSIO_DISPATCH(one, (hi))

If you think it is ugly and want to spend some effort extract an macro, try:

SOLUTION 2

header.hpp

#include <eosiolib/eosio.hpp>

struct [[ eosio::table, eosio::contract(__MY__CONTRACT__)]] test {
  uint64_t prim_key;
  uint64_t timestamp;

  auto primary_key() const { return prim_key; }
};

one.cpp

#define __MY__CONTRACT__ "one"
#include "../header.hpp"
#include <eosiolib/asset.hpp>
#include <eosiolib/eosio.hpp>

using namespace eosio;

CONTRACT one : public contract {
  private:
    typedef multi_index<name("one"), test> test_table;

  public:
    using contract::contract;
    ACTION hi(name user) { print_f("Hello % from one", user); }
};

EOSIO_DISPATCH(one, (hi))

The last solution may not fit your needs as you need the table have same name with contract. However, we use it in our own projects so I would like show it here:

SOLUTION 3

header.hpp

#include <eosiolib/eosio.hpp>

struct test {
  uint64_t prim_key;
  uint64_t timestamp;

  auto primary_key() const { return prim_key; }
};

one.cpp

#include "../header.hpp"
#include <eosiolib/asset.hpp>
#include <eosiolib/eosio.hpp>

using namespace eosio;

CONTRACT one : public contract {
  private:
    TABLE tableone : test{};
    typedef multi_index<name("one"), test> test_table;

  public:
    using contract::contract;
    ACTION hi(name user) { print_f("Hello % from one", user); }
};

EOSIO_DISPATCH(one, (hi))

Conclusion

This can be also done by many other macro tricks and you can pick which ever you like.