Option Parsing

Pixie includes GNU-style command-line parsing and generated help output. Define options once, then parse arguments, read typed values, and generate user-facing help from the same definitions.

Define Options

using Pixie.Options;

var helpFlag = Option.Flag("-h", "--help");
var filesOption = Option.StringSequence("--files")
    .WithParameter("file");

var commandLine = new CommandLine(
    new Option[] { helpFlag },
    filesOption);

Parse And Read Values

using System.Collections.Generic;

var parsedArgs = commandLine.Parse(args, log);

bool showHelp = parsedArgs.GetValue(helpFlag);
IReadOnlyList<string> files = parsedArgs.GetValue(filesOption);

The option object carries the value type, so callers do not repeat it at the read site.

Add Help And Version Handling

var commandLine = new CommandLine(filesOption)
    .WithHelp("Example program.", "example [files-or-options]")
    .WithVersion("example 1.0.0");

var result = commandLine.Parse(args, log);
if (result.WasHandled)
{
    return result.ExitCode;
}

WasHandled is for parser-managed early exits such as generated help or version output. Parse failures are represented by IsSuccess == false.

Handle Failures

var result = commandLine.Parse(args, log);

if (!result.IsSuccess || result.WasHandled)
{
    return result.ExitCode;
}

Parse problems are reported through ILog, which keeps user-facing feedback consistent with the rest of the application.

See It In Context

• ParseOptions shows GNU-style parsing, typed values, suggestions, and errors.
• PrintHelp shows generated help output.