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Smart Contracts

Aptos contracts are written using Move, a next generation language for secure, sandboxed, and formally verified programming which is used for multiple chains. Move allows developers to write programs that flexibly manage and transfer assets while providing security and protections against attacks on those assets.

Here is a hello_blockchain example of move

hello_blockchain.move
module hello_blockchain::message {
use std::error;
use std::signer;
use std::string;
use aptos_framework::event;
//:!:>resource
struct MessageHolder has key {
message: string::String,
}
//<:!:resource
#[event]
struct MessageChange has drop, store {
account: address,
from_message: string::String,
to_message: string::String,
}
/// There is no message present
const ENO_MESSAGE: u64 = 0;
#[view]
public fun get_message(addr: address): string::String acquires MessageHolder {
assert!(exists<MessageHolder>(addr), error::not_found(ENO_MESSAGE));
borrow_global<MessageHolder>(addr).message
}
public entry fun set_message(account: signer, message: string::String)
acquires MessageHolder {
let account_addr = signer::address_of(&account);
if (!exists<MessageHolder>(account_addr)) {
move_to(&account, MessageHolder {
message,
})
} else {
let old_message_holder = borrow_global_mut<MessageHolder>(account_addr);
let from_message = old_message_holder.message;
event::emit(MessageChange {
account: account_addr,
from_message,
to_message: copy message,
});
old_message_holder.message = message;
}
}
#[test(account = @0x1)]
public entry fun sender_can_set_message(account: signer) acquires MessageHolder {
let addr = signer::address_of(&account);
aptos_framework::account::create_account_for_test(addr);
set_message(account, string::utf8(b"Hello, Blockchain"));
assert!(
get_message(addr) == string::utf8(b"Hello, Blockchain"),
ENO_MESSAGE
);
}
}

We have a new Move on Aptos compiler that supports Move 2. See this page for more information.