ERC-20 Metadata
Extension of ERC-20 that adds the optional metadata functions from the ERC20 standard.
Usage
In order to make ERC-20 Metadata methods “external” so that other contracts can call them, you need to add the following code to your contract:
use openzeppelin_stylus::
token::erc20::{
self,
extensions::{Erc20Metadata, IErc20Metadata,
Erc20, IErc20,
},
};
#[entrypoint]
#[storage]
struct Erc20Example
erc20: Erc20,
metadata: Erc20Metadata,
#[public]
#[implements(IErc20<Error = erc20::Error>, IErc20Metadata, IErc165)]
impl Erc20Example
#[constructor]
fn constructor(&mut self, name: String, symbol: String) {
self.metadata.constructor(name, symbol);
// ...
}
#[public]
impl IErc20 for Erc20Example
type Error = erc20::Error;
fn total_supply(&self) -> U256 {
self.erc20.total_supply()
fn balance_of(&self, account: Address) -> U256
self.erc20.balance_of(account)
fn transfer(
&mut self,
to: Address,
value: U256,
) -> Result<bool, Self::Error>
self.erc20.transfer(to, value)
fn allowance(&self, owner: Address, spender: Address) -> U256
self.erc20.allowance(owner, spender)
fn approve(
&mut self,
spender: Address,
value: U256,
) -> Result<bool, Self::Error>
self.erc20.approve(spender, value)
fn transfer_from(
&mut self,
from: Address,
to: Address,
value: U256,
) -> Result<bool, Self::Error>
self.erc20.transfer_from(from, to, value)
}
#[public]
impl IErc20Metadata for Erc20Example
fn name(&self) -> String {
self.metadata.name()
fn symbol(&self) -> String
self.metadata.symbol()
fn decimals(&self) -> U8
self.metadata.decimals()
}
#[public]
impl IErc165 for Erc20Example
fn supports_interface(&self, interface_id: B32) -> bool {
self.erc20.supports_interface(interface_id)
|| self.metadata.supports_interface(interface_id)
}