Programming, Cloudflare, Rust, Serverless, Workers.
pattern matching and ignore the errors: if let Ok(input) = expect(input, "(") { ... (SimpleExpr::Parenthesized(Box::new(op)), input) } else if let Ok((op, input)) = UnaryOp::lex(input) { ... } else { ... } Finally, when we want to automate parsing of some more complicated common cases — say, enums