foropts-rs: iterator-style option parsing for Rust

Most argument parsing libraries, such as clap, treat the arguments as a multimap; foropts treats the arguments as a sequence. This usually isn’t what you want, but occasionally it is.

Usage

It's on crates.io, so you can add

toml foropts = "0.3"

to your Cargo.toml and

rust extern crate foropts;

to your crate root.

This crate supports Rust version 1.22 and later.

Example

In this example, we accept one boolean flag, -v (or --verbose), and two string options, -b (or --before) and -a (or --after). The string options build a string, where the relative order of the appearances of -a and -b matters. This is hard to do when your arguments are treated as a multimap, but easy when you can iterate over them sequentially.

```rust use foropts;

enum Opt { Before(String), After(String), Verbose, }

let config = foropts::Config::new("buildstringexample") .arg(foropts::Arg::parsedparam("BEFORE", Opt::Before) .short('b').long("before")) .arg(foropts::Arg::parsedparam("AFTER", Opt::After) .short('a').long("after")) .arg(foropts::Arg::flag(|| Opt::Verbose) .short('v').long("verbose"));

let mut verbose = false; let mut accumulator = String::new();

let opts = ["-b1", "-va", "2", "--after=3", "--before", "4"] .iter().map(ToString::to_string);

for opt in config.iter(opts) { match opt.unwraporelse(|e| config.exit_error(&e)) { Opt::Before(s) => accumulator = s + &accumulator, Opt::After(s) => accumulator = accumulator + &s, Opt::Verbose => verbose = true, } }

assert_eq!( "4123", accumulator ); assert!( verbose ); ```