sui-move-patternslisted

## 1. Events Emit events for all state-changing operations that clients need to observe: ```move use sui::event; public struct LiquidityAdded has copy, drop { pool_id: ID, amount_x: u64, amount_y: u64, lp_minted: u64, } // Inside function: event::emit(LiquidityAdded { pool_id: object::id(pool), amount_x, amount_y, lp_minted, }); ``` --- ## 2. Error Handling Error constants use `EPascalCase` and `u64` values: ```move const EInsufficientLiquidity: u64 = 0; const EZeroAmount: u64 = 1; assert!(amount > 0, EZeroAmount); ``` ### Clever errors Annotating a constant with `#[error]` allows it to carry a human-readable message. The value can be any valid constant type — `vector<u8>` is most common for string messages: ```move #[error] const EInsufficientLiquidity: vector<u8> = b"Insufficient liquidity in pool"; assert!(reserves > 0, EInsufficientLiquidity); abort EInsufficientLiquidity ``` At runtime, the Sui CLI and GraphQL server automatically decode these into a readable message: ``` Error from '0x2::amm::swap' (line 42), abort 'EInsufficientLiquidity': "Insufficient liquidity in pool" ``` **Gotcha**: clever error abort codes encode the source line number, so their `u64` value can change if the file is reformatted or lines shift. Don't hardcode clever error abort codes in tests or off-chain tooling — match by constant name instead. `**assert!` without an abort code** is also valid and auto-derives a clever abort code from the source l