mystenlabs/sui-dev-skills/objects

// ✅
public struct Pool has key {
    id: UID,
    balance_x: Balance<SUI>,
    balance_y: Balance<USDC>,
}
 
public struct PoolCap has key, store {
    id: UID,
    pool_id: ID,
}
 
// ❌ Legacy — no public keyword
struct Pool has key {
    id: UID,
}

// ✅
public struct AdminCap has key, store { id: UID }
 
// ❌ Unclear it's a capability
public struct Admin has key, store { id: UID }

// ✅
public struct Promise {}
 
// ❌
public struct PromisePotato {}

// ✅
public struct LiquidityAdded has copy, drop { ... }
public struct FeesCollected has copy, drop { ... }
 
// ❌
public struct AddLiquidity has copy, drop { ... }
public struct CollectFees has copy, drop { ... }

// ✅
public struct BalanceKey() has copy, drop, store;
 
// ⚠️ Acceptable but not canonical
public struct BalanceKey has copy, drop, store {}

// ✅
const ENotAuthorized: u64 = 0;
const MAX_FEE_BPS: u64 = 10_000;
 
// ❌
const NOT_AUTHORIZED: u64 = 0;   // error should be EPascalCase
const MaxFeeBps: u64 = 10_000;   // non-error should be ALL_CAPS

// Transfer to an address (owned object)
transfer::transfer(obj, recipient);             // key only — module-restricted
transfer::public_transfer(obj, recipient);      // key + store — usable anywhere
 
// Share (accessible by anyone, goes through consensus)
transfer::share_object(obj);                    // key only — module-restricted
transfer::public_share_object(obj);             // key + store
 
// Freeze (immutable forever)
transfer::freeze_object(obj);                   // key only — module-restricted
transfer::public_freeze_object(obj);            // key + store

use sui::dynamic_field as df;
use sui::dynamic_object_field as dof;
 
// Add a dynamic field (value stored inline with parent)
df::add(&mut parent.id, key, value);
 
// Add a dynamic object field (value is an independent object)
dof::add(&mut parent.id, key, child_obj);
 
// Access
let val: &MyType = df::borrow(&parent.id, key);
let val: &mut MyType = df::borrow_mut(&mut parent.id, key);
 
// Remove
let val: MyType = df::remove(&mut parent.id, key);