Token Interface

pub trait TokenInterface {
    /// Returns the allowance for `spender` to transfer from `from`.
    ///
    /// # Arguments
    ///
    /// * `from` - The address holding the balance of tokens to be drawn from.
    /// * `spender` - The address spending the tokens held by `from`.
    fn allowance(env: Env, from: Address, spender: Address) -> i128;
 
    /// Set the allowance by `amount` for `spender` to transfer/burn from
    /// `from`.
    ///
    /// # Arguments
    ///
    /// * `from` - The address holding the balance of tokens to be drawn from.
    /// * `spender` - The address being authorized to spend the tokens held by
    ///   `from`.
    /// * `amount` - The tokens to be made available to `spender`.
    /// * `expiration_ledger` - The ledger number where this allowance expires. Cannot
    ///    be less than the current ledger number unless the amount is being set to 0.
    ///    An expired entry (where expiration_ledger < the current ledger number)
    ///    should be treated as a 0 amount allowance.
    ///
    /// # Events
    ///
    /// Emits an event with topics `["approve", from: Address,
    /// spender: Address], data = [amount: i128, expiration_ledger: u32]`
    fn approve(env: Env, from: Address, spender: Address, amount: i128, expiration_ledger: u32);
 
    /// Returns the balance of `id`.
    ///
    /// # Arguments
    ///
    /// * `id` - The address for which a balance is being queried. If the
    ///   address has no existing balance, returns 0.
    fn balance(env: Env, id: Address) -> i128;
 
    /// Transfer `amount` from `from` to `to`.
    ///
    /// # Arguments
    ///
    /// * `from` - The address holding the balance of tokens which will be
    ///   withdrawn from.
    /// * `to` - The address which will receive the transferred tokens.
    /// * `amount` - The amount of tokens to be transferred.
    ///
    /// # Events
    ///
    /// Emits an event with topics `["transfer", from: Address, to: Address],
    /// data = [amount: i128]`
    fn transfer(env: Env, from: Address, to: Address, amount: i128);
 
    /// Transfer `amount` from `from` to `to`, consuming the allowance of
    /// `spender`. Authorized by spender (`spender.require_auth()`).
    ///
    /// # Arguments
    ///
    /// * `spender` - The address authorizing the transfer, and having its
    ///   allowance consumed during the transfer.
    /// * `from` - The address holding the balance of tokens which will be
    ///   withdrawn from.
    /// * `to` - The address which will receive the transferred tokens.
    /// * `amount` - The amount of tokens to be transferred.
    ///
    /// # Events
    ///
    /// Emits an event with topics `["transfer", from: Address, to: Address],
    /// data = [amount: i128]`
    fn transfer_from(env: Env, spender: Address, from: Address, to: Address, amount: i128);
 
    /// Burn `amount` from `from`.
    ///
    /// # Arguments
    ///
    /// * `from` - The address holding the balance of tokens which will be
    ///   burned from.
    /// * `amount` - The amount of tokens to be burned.
    ///
    /// # Events
    ///
    /// Emits an event with topics `["burn", from: Address], data = [amount:
    /// i128]`
    fn burn(env: Env, from: Address, amount: i128);
 
    /// Burn `amount` from `from`, consuming the allowance of `spender`.
    ///
    /// # Arguments
    ///
    /// * `spender` - The address authorizing the burn, and having its allowance
    ///   consumed during the burn.
    /// * `from` - The address holding the balance of tokens which will be
    ///   burned from.
    /// * `amount` - The amount of tokens to be burned.
    ///
    /// # Events
    ///
    /// Emits an event with topics `["burn", from: Address], data = [amount:
    /// i128]`
    fn burn_from(env: Env, spender: Address, from: Address, amount: i128);
 
    /// Returns the number of decimals used to represent amounts of this token.
    ///
    /// # Panics
    ///
    /// If the contract has not yet been initialized.
    fn decimals(env: Env) -> u32;
 
    /// Returns the name for this token.
    ///
    /// # Panics
    ///
    /// If the contract has not yet been initialized.
    fn name(env: Env) -> String;
 
    /// Returns the symbol for this token.
    ///
    /// # Panics
    ///
    /// If the contract has not yet been initialized.
    fn symbol(env: Env) -> String;
}