argonaut 0.8.0

A simple argument parser
Documentation

Argonaut

An argument parser for Rust, that grants as much control over the parser as possible.

Argument conversion

This means that the arguments are not converted to other types (except for switches that are boolean by default).

Help messages

It also means that help messages are not handled either. Just write it yourself, and make it NICE!

Error handling

The actual argument parsing returns errors that should be pretty simple to convey to users, but these are not handled by the parser either.

Adding arguments to the parser and accessing arguments on the parsed arguments will only return an error string, as they may only have logical errors, such as adding arguments that would overwrite each other, or trying to access a parsed argument using an invalid identifier.

Example

This can be found in examples/main.rs as well, and be run with cargo run --example main -- foo bar -x baz --verbose -e extra1 extra2 --add -- lol --help. You can also try running it without the arguments, but these arguments will make the parse succeed.

extern crate argonaut;

use argonaut::{Parser, Arg};
use std::env;

fn main() {
    use argonaut::StructuredArgument::*;
    println!("Argonaut!");
    
    // Prepare the argument slice (skip the program path)
    let arg_vec: Vec<_> = env::args().skip(1).collect();
    let mut args: Vec<&str> = Vec::new();
    for arg in arg_vec.iter() {
        args.push(arg);
    }
    
    println!("Args: {:?}", args);
    
    let mut parser = Parser::new();
    
    // Create the arguments
    let foo     = Arg::positional("foo");
    let bar     = Arg::required_trail();
    let help    = Arg::named_and_short("help", 'h').interrupt();
    let version = Arg::named("version").interrupt();
    let verbose = Arg::named_and_short("verbose", 'v').switch();
    let exclude = Arg::named_and_short("exclude", 'x').single();
    let extra   = Arg::named_and_short("extra", 'e').zero_or_more();
    let add     = Arg::named_and_short("add", 'a').one_or_more();
    let passed  = Arg::named("").passalong();
    
    // Add them, and assert that none of the named ones overlap
    parser.add(&foo).unwrap();
    parser.add(&bar).unwrap();
    parser.add(&help).unwrap();
    parser.add(&version).unwrap();
    parser.add(&verbose).unwrap();
    parser.add(&exclude).unwrap();
    parser.add(&extra).unwrap();
    parser.add(&add).unwrap();
    parser.add(&passed).unwrap();
        
    let mut foo = "";
    let mut bar = Vec::new();
    let mut extra = None;
    let mut add = None;
    let mut verbose = false;
    let mut exclude = None;
    let mut passed = None;
    
    let usage = "Usage: cargo run --example main -- [--help] [options]";
    let help = "\
Required arguments:    
foo             a single argument
bar [bar, ..]   one or more arguments

Interrupts:
--help | -h     show this help message
--version       show the version of this library

Optional arguments:
--verbose | -v              a switch (present or non-present)
--extra | -e [arg, ..]      zero or more arguments
--add | -a arg [arg, ..]    one or more arguments
--                          collect the remaining arguments\
";
    
    for item in parser.parse(&args) {
        match item {
            Err(err) => {
                println!("Parse error: {:?}", err);
                println!("{}", usage);
                return;
            },
            Ok(Positional { name: "foo", value }) => {
                foo = value;
            },
            Ok(Trail { values }) => {
                bar = values;
            },
            Ok(Interrupt { name: "help" }) => {
                println!("{}\n{}", usage, help);
            },
            Ok(Interrupt { name: "version" }) => {
                println!("{}", env!("CARGO_PKG_VERSION"));
            },
            Ok(Switch { name: "verbose" }) => {
                verbose = true;
            },
            Ok(Single { name: "exclude", parameter }) => {
                exclude = Some(parameter);
            },
            Ok(Multiple { name: "add", parameters }) => {
                add = Some(parameters);
            },
            Ok(Multiple { name: "extra", parameters }) => {
                extra = Some(parameters);
            },
            Ok(PassAlong { name: "", args }) => {
                passed = Some(args);
            },
            _ => unreachable!(),
        }
    }
    // Use the parsed values
    println!("Parsed succesfully!");
    println!("Foo:          {}", foo);
    println!("Bar:          {:?}", bar);
    println!("Verbose:      {}", verbose);
    println!("Exclude:      {:?}", exclude);
    println!("Extra:        {:?}", extra);
    println!("Add:          {:?}", add);
    println!("Passed args:  {:?}", passed);
}

Terminology

Flag: The identifying token for an argument (--flag) Switch: A flag with no arguments that is either there or not there Parameter: Tokens following an argument. Trail: Zero or more tokens that follow the required positional arguments.

License

Licensed under either of

at your option.

Contribution

Unless you explicitly state otherwise, any contribution intentionally submitted for inclusion in the work by you, as defined in the Apache-2.0 license, shall be dual licensed as above, without any additional terms or conditions.