ArgsParser 3.0.0

ArgsParser

Easy argument parsing for .Net Core applications.

Example usage

using ArgsParser;

// other code

var parser = new Parser(args)
    .SupportsOption<int>("port", "Port to start the dev server on", 1337)
    .RequiresOption<string>("read", "Folder to read the site from", "site")
    .RequiresOption<string>("write", "Folder to write the result to")
    .SupportsFlag("serve", "Start the site going in a dev server")
    .SupportsFlag("force", "Overwrite any destination content")
    .Help();

parser.Parse();

var hasError = parser.HasErrors;
var serve = parser.IsFlagProvided("serve");
var port = parser.GetOption<int>("port");
var read = parser.GetOption<string>("read");

Example autogenerated help info (.Help())

• Required options come first, then optional options, then flags
• Each of those three blocks is further sorted alphabetically

-read  <value>   Folder to read the site from (required)
-write <value>   Folder to write the result to (required)
-port  <value>   Port to start the dev server on

-force           Overwrite any destination content
-serve           Start the site going in a dev server

Example input

mycommand -run data "Site Title" --serve -ignore -port 3000

Example errors from the above

Errors come in two collections. The property HasErrors will be true if either collection has entries.

• ExpectationErrors are where expectations are not met by the arguments provided (eg missing required option)
• ArgumentErrors are where something was provided but there were issues with it (eg a value without an option)

For example, with the configuration above and the example input shown the combined errors will be as follows.

write => Option missing: write
0 => Unknown option: run
2 = Unexpected value: Site Title
4 => Unknown flag: ignore

• The first is an expectation error and is keyed by the name of the option
• The remaining three are argument errors keyed by their 0-based offset into the args provided
• The "missing" read option has no error; it was defined above with a default value

Supported

• Display help showing supported flags/options
• Required named option/values
• Optional named option/values
• Optional named flags
• Default option values
• Option types support any IConvertable, including int, bool, DateTime
• Accepts either - or -- prefixes
• Provides two collections of error messages
  • Expectation errors
    • Missing required options
  • Argument errors
    • Option values of incorrect type
    • Unexpected values (not with an option)
    • Unnamed flags or options
    • Unknown flags or options

The example in detail

The assertions, which are provided for clarity, are from NUnit.

var args = new string[] { "-run", "data", "Site Title", "--serve", "-ignore", "-port", "3000" };

var parser = new Parser(args)
    .SupportsOption<int>("port", "Port to start the dev server on", 1337)
    .RequiresOption<string>("read", "Folder to read the site from", "site")
    .RequiresOption<string>("write", "Folder to write the result to")
    .SupportsFlag("serve", "Start the site going in a dev server")
    .SupportsFlag("force", "Overwrite any destination content")
    .Help();

var result = parser.Parse();

Assert.AreEqual(4, result.ExpectationErrors.Count + result.ArgumentErrors.Count);
Assert.Contains("Option missing: write", result.ExpectationErrors.Values.ToList());
Assert.Contains("Unknown option: run", result.ArgumentErrors.Values.ToList());
Assert.Contains("Unexpected value: Site Title", result.ArgumentErrors.Values.ToList());
Assert.Contains("Unknown flag: ignore", result.ArgumentErrors.Values.ToList());

Assert.IsTrue(result.IsOptionProvided("port"));
Assert.AreEqual(3000, result.GetOption<int>("port"));

Assert.IsTrue(result.IsOptionProvided("read"));
Assert.AreEqual("site", result.GetOption<string>("read"));

Assert.IsFalse(result.IsOptionProvided("write"));
Assert.AreEqual(null, result.GetOption<string>("write"));

Assert.IsTrue(result.IsFlagProvided("serve"));
Assert.IsFalse(result.IsFlagProvided("force"));

Copyright K Cartlidge 2020. Licensed as GNU AGPLv3.