Mastering Rust - Second Edition

Impl blocks for enums

We can also provide implementations for enums. For example, consider a payments library built in Rust, which exposes a single API called pay:

// enum_methods.rsenum PaymentMode {    Debit,    Credit,    Paypal}// Bunch of dummy payment handlersfn pay_by_credit(amt: u64) {    println!("Processing credit payment of {}", amt);}fn pay_by_debit(amt: u64) {    println!("Processing debit payment of {}", amt);}fn paypal_redirect(amt: u64) {    println!("Redirecting to paypal for amount: {}", amt);}impl PaymentMode {    fn pay(&self, amount: u64) {        match self {            PaymentMode::Debit => pay_by_debit(amount),            PaymentMode::Credit => pay_by_credit(amount),            PaymentMode::Paypal => paypal_redirect(amount)        }    }}fn get_saved_payment_mode() -> PaymentMode { PaymentMode::Debit ...