[Feature] Support for global variables

[tanqiangyes]

🚀 Feature

Support for global variables to make programs more diverse

Motivation

program global.aleo {
         let  global_address: address;
         let  is_set = bool;

        transition deploy(addr: address) -> bool {
              if is_set {
                  return false;
              }
              global_address = addr;
              is_set = true;
          }

          transition change_deploy(addr: address, new_addr: address) -> bool {
                if addr != global_address {
                    return false;
                }
                global_address = new_addr;
            }

         //some other features.
}

As you can see, if global variables are implemented, then when writing a game-like contract, players send their game pledges to the contract deployer, so that no player can raise the pledge privately, and the contract deployer can use zero-knowledge proofs to control the access to the game funds through the application made by the player, which greatly ensures the financial security and fairness of the contract.

Implementation

As it stands now, it may be necessary to modify variable declarations, as well as the internal constructs of the program and the corresponding compiler. This will be a lot of work, but it will be a huge boost to the programming effort.

[d0cd]

Thank you for the proposal! We are definitely open to introducing this into the language. We will need to iron out details of the design and programming model in an ARC. Here are some relevant links:

• https://github.com/AleoHQ/ARCs
• https://github.com/AleoHQ/ARCs/discussions

[tanqiangyes]

Thank you for the proposal! We are definitely open to introducing this into the language. We will need to iron out details of the design and programming model in an ARC. Here are some relevant links:

• https://github.com/AleoHQ/ARCs
• https://github.com/AleoHQ/ARCs/discussions

Here is:

• https://github.com/AleoHQ/ARCs/pull/27
• https://github.com/AleoHQ/ARCs/discussions/26

[tanqiangyes]

@d0cd Please review the latest ARC, thanks.