examples/token.cell

// Playground teaching note: // Start here: this example shows the Cell lifecycle for a simple token. // Follow the consume/create/destroy lines; they are the core of CellScript. module cellscript::fungible_token const U64_MAX: u64 = 18446744073709551615 resource Token has store, create, consume, replace, burn, relock { amount: u64, symbol: [u8; 8], } resource MintAuthority has store, create, replace { token_symbol: [u8; 8], max_supply: u64, minted: u64, } action mint_with_authority(auth_before: MintAuthority, to: Address, amount: u64) -> (auth_after: MintAuthority, token: Token) { transition auth_before -> auth_after verification require amount <= U64_MAX - auth_before.minted, "mint overflow" require auth_before.minted + amount <= auth_before.max_supply, "exceeds max supply" require auth_after.token_symbol == auth_before.token_symbol require auth_after.max_supply == auth_before.max_supply require auth_after.minted == auth_before.minted + amount create token = Token { amount, symbol: auth_before.token_symbol } with_lock(to) } action transfer_token(token: Token, to: Address) -> next_token: Token { verification consume token create next_token = Token { amount: token.amount, symbol: token.symbol } with_lock(to) } action burn(token: Token) { verification require token.amount > 0, "cannot burn zero" destroy token } action merge(a: Token, b: Token, to: Address) -> merged: Token { verification require a.symbol == b.symbol, "symbol mismatch" require b.amount <= U64_MAX - a.amount, "amount overflow" let total = a.amount + b.amount consume a consume b create merged = Token { amount: total, symbol: a.symbol } with_lock(to) }