mod parser; fn main() -> Result<(), lexopt::Error> { let args = Args::parse()?; let input = args.input.as_deref().unwrap_or( "GET / HTTP/1.1 Host: www.reddit.com User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.8; rv:15.0) Gecko/20100101 Firefox/15.0.1 Accept: text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8 Accept-Language: en-us,en;q=0.5 Accept-Encoding: gzip, deflate Connection: keep-alive ", ); if let Some(result) = parser::parse(input.as_bytes()) { println!(" {:#?}", result); } Ok(()) } #[derive(Default)] struct Args { input: Option, } impl Args { fn parse() -> Result { use lexopt::prelude::*; let mut res = Args::default(); let mut args = lexopt::Parser::from_env(); while let Some(arg) = args.next()? { match arg { Value(input) => { res.input = Some(input.string()?); } _ => return Err(arg.unexpected()), } } Ok(res) } }