Simple state
The state is where the smart contract saves and retrieves data. In a sense, the smart contract state functions similarly to a database interaction layer in a traditional application.
The simplest method of representing state involves storing a single item. For instance, in the cw20 contract, the TokenInfo is recorded during the contract's initialization.
First, a TokenInfo type is declared in state.rs:
#[derive(Serialize, Deserialize, Clone, PartialEq, JsonSchema, Debug)]#[serde(rename_all = "snake_case")]pub struct TokenInfo { pub name: String, pub symbol: String, pub decimals: u8, pub total_supply: Uint128, pub mint: Option<MinterData>,}
Then the storage is initialized:
pub const TOKEN_INFO: Item<TokenInfo> = Item::new("token_info");
In the contract, we see in the instantiate function how data can be saved to this:
let data = TokenInfo { name: msg.name, symbol: msg.symbol, decimals: msg.decimals, total_supply, mint,};TOKEN_INFO.save(deps.storage, & data) ?;
You can get the cw20 base contract by choosing it as the starter template when setting up the project via the archway CLI