storing and getting structs

[enderNakamoto]

Discord user ID

enderwiggins

Describe your question in detail.

Hi, this example - https://learn.aptoslabs.com/en/tutorials/aptos-101/move-language/modules?workshop=web3-to-aptos has an inconsistency, but more likely I do not understand something:

Here's the code:

module aptogotchi::main {

	  struct Config has copy, drop {
	  	admin: address
	  }

      // Init function runs once when the module is published for the first time.
	  fun init_module(caller: &signer) {
        let caller_addr = address_of(caller);

        // move_to is a function to move the struct to the global storage
        move_to(caller, Config { admin: caller_addr });
    }

    #[view]
    public fun get_admin(): address acquires Config {
        // @aptogotchi is the address of the module
        let config = borrow_global<Config>(@aptogotchi);

        config.admin
    }
}

Questions

1. if the struct is stored in caller - move_to(caller, Config { admin: caller_addr });, how is it retreived from module address? let config = borrow_global(@aptogotchi);. Are caller/module address same? in that case, isn't admin just aptogotchi??

2. why does Config has copy, drop, shouldn't it have key as it is stored in an address?

[gregnazario]

if the struct is stored in caller - move_to(caller, Config { admin: caller_addr });, how is it retreived from module address? let config = borrow_global(@aptogotchi);. Are caller/module address same? in that case, isn't admin just aptogotchi??

init_module is called on publishing of a module, with the publisher's signer. The publisher's address is the same address as the module (in this case aptogotchi), so they are the same address.

And yes, in this case admin is @aptogotchi, but it could be changed to something else.

why does Config has copy, drop, shouldn't it have key as it is stored in an address?

This one should most certainly have key, I'm guessing it was inconsistent cc @0xaptosj

[0xaptosj]

yeah it should have key capability. FIxed and should be live soon