Interface Registry

[robert-zaremba]

For composability, smart contracts will need to have a priory knowledge about other smart contract interfaces. It will be extremely useful to store that information on chain:

• smart contract designers could verify which interfaces are popular
• when a smart contract will like to add / register other smart contract it may use the interface register to check for expected interfaces.

The mechanism is simple. A smart contract must call the registry and register itself. So only smart contract can do self registration, no one else can register a smart contract.
In the future version, however, we may consider a DAO mechanism, to allow the registration of older contract.

trait InterfaceRegistry {
    fn ir_implements(&self, interface: uint32, smart_contract: string) -> bool;
    fn ir_implements_many(&self, interface: uint32, smart_contract: Vec<string>) -> Vec<bool>;

    // smart contract self registration and un-registration
    fn ir_register(&mut self, interface: uint32);
    fn ir_unregister(&mut self, interface: uint32);
}

[robert-zaremba]

This can be implemented as a Curated List.

[mfornet]

@robert-zaremba who will be able to call ir_register? It could be either the contract itself, or a centralized authority. I wrote a similar approach some time ago: #275. I like the simplicity of this approach.

[robert-zaremba]

Probably yes, but then we need to have some authorization mechanism.

So, only smart contract should register and de-register itself. I will update the spec.

[mfornet]

Do we need to have ir_unregister? Some scenarios come to my mind:

• Error interacting with registry (maybe impossible if access is properly set)
• Target contract changed (it was upgraded)

[frol]

I want to bring up the fact that ABI for contracts on NEAR is approaching stabilization. It will embed the schema definition right in the contract itself. Yet, legacy contracts and JS / AS contracts are not supported yet.

[robert-zaremba]

will other smart contracts be able to query for the supported methods ?

[frol]

Absolutely, the ABI is exposed as a view-function call, so other contracts can just do a cross-contract call to fetch it.