argd

argd is a lightweight, class-based argument and command parsing system for the D programming language. It allows for easy creation of complex command-line interfaces with nested subcommands, automated help generation, and argument validation.

Features

• Nested Subcommands: Create hierarchical CLI tools (like git or dub).
• Automated Help: Automatically generates usage instructions and subcommand/option lists.
• Argument Validation: Specify expected argument counts and collection types.
• Option Handling: Simple registration and retrieval of long and short-form options.
• Cross-Platform: Built using standard D libraries (std.*).

Installation

Add argd as a dependency in your dub.json:

"dependencies": {
    "argd": "~>0.0.1"
}

Quick Start

import argd;
import std.stdio;

class GreetCommand : Command {
    this() {
        super("greet");
        description = "Greets a person";
        usage = "<name>";
        argCount = 1;
        argCollType = ArgCollectionType.exact;
        
        addOption("--formality", "-f", "Use formal greeting");
    }

    override protected CommandResult onExecute(string[] args, bool verbose, bool quiet) {
        string name = args[0];
        bool formal = hasOption("--formality", "-f");
        
        if (formal) {
            writeln("Greetings, ", name, ".");
        } else {
            writeln("Hello, ", name, "!");
        }
        
        return CommandResult.ok();
    }
}

void main(string[] args) {
    auto root = new GreetCommand();
    auto result = root.handle(args[1 .. $]);

    // Check if there is a message to display (like help or errors)
    if (result.message.length > 0) {
        if (result.success) {
            writeln(result.message);
        } else {
            stderr.writeln(result.message);
        }
    }
}

Examples

Check out the examples/ directory for a complete demonstration of a multi-command CLI. You can run it directly using Dub:

dub run :basic -- greet "World" --formality

License

This project is licensed under the MIT License.