1. Common Standard Library Patterns
// Strings — use method syntax, don't import utf8
let s: String = b"hello".to_string();
let ascii: ascii::String = b"hello".to_ascii_string();
// Coin and Balance
use sui::coin::{Self, Coin};
use sui::balance::{Self, Balance};
let balance: Balance<SUI> = coin.into_balance();
let coin: Coin<SUI> = balance.into_coin(ctx); // ✅ method syntax
let amount: u64 = coin.value();
// Split a payment
let exact = payment.split(amount, ctx); // ✅
let exact = payment.balance_mut().split(amount); // ✅ avoids ctx
// Consuming values without drop — the @0x0 burn pattern
//
// Move's linear type system requires every non-drop value to be
// explicitly consumed. The _ prefix only suppresses warnings for values
// that do have drop — it won't help for Balance, Coin, or your
// own structs that lack drop.
//
// To permanently destroy any key + store object, transfer it to @0x0
// (an address no one controls, equivalent to Solidity's address(0)):
transfer::public_transfer(my_obj, @0x0); // ✅ permanent burn
//
// Balance has neither drop nor key, so it cannot be transferred
// directly, and balance::destroy_zero only works on empty balances.
// Wrap it in a Coin first:
//
// let _locked = supply.increase_supply(MINIMUM_LIQUIDITY); // ❌ compile error
//
let locked = supply.increase_supply(MINIMUM_LIQUIDITY).into_coin(ctx);
transfer::public_transfer(locked, @0x0); // ✅ burns the minimum liquidity
//
// Hot potatoes (structs with no abilities at all) cannot use this pattern —
// they must be destructured and each field consumed individually.
// Option let opt: Option = option::some(42); let val = opt.destroy_or!(default_value); // ✅ macro form let val = opt.borrow();
// Address and IDs let id: ID = object::id(&my_obj); let addr: address = id.to_address();
// UID deletion id.delete(); // ✅ // object::delete(id); // ❌ verbose
// TxContext sender ctx.sender() // ✅ // tx_context::sender(ctx) // ❌ verbose
// Vector literals and index syntax let mut v = vector[1, 2, 3]; // ✅ literal let first = v[0]; // ✅ index syntax assert!(v.length() == 3); // ✅ method syntax // let mut v = vector::empty(); // ❌ verbose // vector::push_back(&mut v, 1); // ❌ verbose
// Struct unpack — use .. to ignore fields you don't need let MyStruct { id, .. } = value; // ✅ // let MyStruct { id, field_a: _, field_b: _ } = value; // ❌ verbose