use winnow::prelude::*; mod parser; use parser::hex_color; fn main() -> Result<(), lexopt::Error> { let args = Args::parse()?; let input = args.input.as_deref().unwrap_or("#AAAAAA"); println!("{} =", input); match hex_color.parse(input) { Ok(result) => { println!(" {:?}", result); } Err(err) => { println!(" {}", err); } } 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) } } #[test] fn parse_color() { assert_eq!( hex_color.parse_peek("#2F14DF"), Ok(( "", parser::Color { red: 47, green: 20, blue: 223, } )) ); }