### 📟 zli - a blazing-fast CLI framework for Zig.

Build modular, ergonomic, and high-performance CLIs with ease.

Batteries included. [ZLI reference docs](https://xcaeser.github.io/zli)

[![Tests](https://github.com/xcaeser/zli/actions/workflows/main.yml/badge.svg)](https://github.com/xcaeser/zli/actions/workflows/main.yml)
[![Zig Version](https://img.shields.io/badge/Zig_Version-0.16.0-orange.svg?logo=zig)](README.md)
[![License: MIT](https://img.shields.io/badge/License-MIT-lightgrey.svg?logo=cachet)](LICENSE)
[![Built by xcaeser](https://img.shields.io/badge/Built%20by-@xcaeser-blue)](https://github.com/xcaeser)
[![Version](https://img.shields.io/badge/ZLI-v5.1.2-green)](https://github.com/xcaeser/zli/releases)

## 🚀 Features

- Modular commands & subcommands
- Fast flag parsing (`--flag`, `--flag=value`, shorthand `-abc`)
- Type-safe support for `bool`, `int`, `string`
- Named positional arguments with `required`, `optional`, `variadic`
- Auto help/version/deprecation handling
- Pretty help output with aligned flags & args
- Spinners for a more interactive experience
- Usage hints, context-aware

## 📦 Installation

```sh
zig fetch --save=zli https://github.com/xcaeser/zli/archive/v5.1.2.tar.gz
```

Add to your `build.zig`:

```zig
const zli_dep = b.dependency("zli", .{ .target = target, .optimize = optimize });
exe.root_module.addImport("zli", zli_dep.module("zli"));
```

## 🌱 Single-file Quick Start

Start with one `src/main.zig`: initialize the root command, add a flag, add a subcommand, then run it.

```zig
const std = @import("std");
const Io = std.Io;
const zli = @import("zli");

pub fn main(init: std.process.Init) !void {
    const io = init.io;

    var wbuf: [1024]u8 = undefined;
    var stdout_writer = Io.File.Writer.init(.stdout(), io, &wbuf);
    const stdout = &stdout_writer.interface;
    defer stdout.flush() catch {};

    var rbuf: [1024]u8 = undefined;
    var stdin_reader = Io.File.Reader.init(.stdin(), io, &rbuf);
    const stdin = &stdin_reader.interface;

    const init_options = zli.InitOptions{
        .allocator = init.gpa,
        .io = io,
        .writer = stdout,
        .reader = stdin,
    };

    const root = try zli.Command.init(init_options, .{
        .name = "hello",
        .description = "A tiny zli app",
        .version = .{ .major = 0, .minor = 1, .patch = 0, .pre = null, .build = null },
    }, showHelp);

    try root.addFlag(.{
        .name = "verbose",
        .shortcut = "v",
        .description = "Print more details",
        .type = .Bool,
        .default_value = .{ .Bool = false },
        .persistent = true,
    });

    const greet = try zli.Command.init(init_options, .{
        .name = "greet",
        .description = "Greet someone",
    }, greetSomeone);
    try greet.addPositionalArg(.{
        .name = "name",
        .description = "Who to greet",
        .required = true,
    });
    try root.addCommand(greet);

    var args_iter = init.minimal.args.iterate();
    root.runAndExit(&args_iter, .{});
}

fn showHelp(ctx: zli.CommandContext) !void {
    try ctx.command.printHelp();
}

fn greetSomeone(ctx: zli.CommandContext) !void {
    const verbose = ctx.flag("verbose", bool);
    const name = ctx.getArg("name") orelse "friend";

    if (verbose) {
        try ctx.writer.print("Preparing greeting for {s}\n", .{name});
    }

    try ctx.writer.print("Hello, {s}!\n", .{name});
}
```

Run it:

```sh
zig build run -- greet Ada
zig build run -- --verbose greet Ada
zig build run -- greet Ada --help
```

Use `runAndExit` for normal CLI binaries: it prints errors/help and exits with the right process code. Use `execute` when you want library-friendly behavior for tests, embedding, or custom error handling; it returns errors instead of exiting the process.

## 🗂 Folder Structure (but you can do what you want)

```
your-app/
├── build.zig
├── src/
│   ├── main.zig
│   └── cli/
│       ├── root.zig // zli entrypoint
│       ├── run.zig  // subcommand 1
│       └── version.zig // subcommand 1
        ... // subcommand of subcommands, go nuts
```

- Each command is in its own file
- You explicitly register subcommands
- `root.zig` is the entry point

## 🧪 Example

### Your program

```zig
// src/main.zig
const std = @import("std");
const Io = std.Io;

const cli = @import("cli/root.zig");

pub fn main(init: std.process.Init) !void {
    const io = init.io;

    var wbuf: [1024]u8 = undefined;
    var stdout_writer = Io.File.Writer.init(.stdout(), io, &wbuf);
    const stdout = &stdout_writer.interface;
    defer stdout.flush() catch {};

    var rbuf: [1024]u8 = undefined;
    var stdin_reader = Io.File.Reader.init(.stdin(), io, &rbuf);
    const stdin = &stdin_reader.interface;

    const root = try cli.build(.{
        .allocator = init.gpa,
        .io = io,
        .writer = stdout,
        .reader = stdin,
    });

    var argsIter = init.minimal.args.iterate();
    root.runAndExit(&argsIter, .{}); // Or pass data with: root.runAndExit(&argsIter, .{ .data = &my_data });
}
```

### Root command - entrypoint

```zig
// src/cli/root.zig
const std = @import("std");
const zli = @import("zli");

const run = @import("run.zig");
const version = @import("version.zig");

pub fn build(init_options: zli.InitOptions) !*zli.Command {
    const root = try zli.Command.init(init_options, .{
        .name = "blitz",
        .description = "Your dev toolkit CLI",
        .version = .{ .major = 0, .minor = 0, .patch = 1, .pre = null, .build = null },
    }, showHelp);

    try root.addCommands(&.{
        try run.register(init_options),
        try version.register(init_options),
    });

    return root;
}

fn showHelp(ctx: zli.CommandContext) !void {
    try ctx.command.printHelp();
}
```

### Run subcommand

```zig
// src/cli/run.zig
const std = @import("std");
const zli = @import("zli");

const now_flag = zli.Flag{
    .name = "now",
    .shortcut = "n",
    .description = "Run immediately",
    .type = .Bool,
    .default_value = .{ .Bool = false },
};

pub fn register(init_options: zli.InitOptions) !*zli.Command {
    const cmd = try zli.Command.init(init_options, .{
        .name = "run",
        .description = "Run your workflow",
    }, run);

    try cmd.addFlag(now_flag);
    try cmd.addPositionalArg(.{
        .name = "script",
        .description = "Script to execute",
        .required = true,
    });
    try cmd.addPositionalArg(.{
        .name = "env",
        .description = "Environment name",
        .required = false,
    });

    return cmd;
}

fn run(ctx: zli.CommandContext) !void {
    const now = ctx.flag("now", bool); // type-safe flag access

    const script = ctx.getArg("script") orelse {
        try ctx.writer.print("Missing script arg\n", .{});
        return;
    };
    const env = ctx.getArg("env") orelse "default";

    std.debug.print("Running {s} in {s} (now = {})\n", .{ script, env, now });

    // You can also get other commands by name:
    // if (ctx.root.findCommand("create")) |create_cmd| {
    //    try create_cmd.printUsageLine();
    // }

    // if you passed data to your root command, you can access it here:
    // const object = ctx.getContextData(type_of_your_data); // can be struct, []const u8, etc., object is a pointer.

};
```

### Version subcommand

```zig
// src/cli/version.zig
const std = @import("std");
const zli = @import("zli");

pub fn register(init_options: zli.InitOptions) !*zli.Command {
    return zli.Command.init(init_options, .{
        .name = "version",
        .shortcut = "v",
        .description = "Show CLI version",
    }, show);
}

fn show(ctx: zli.CommandContext) !void {
    try ctx.root.printVersion();
}
```

### Spinners example

Available functions:

- `spinner.start`: to add a new line. sets the spinner to running
- `spinner.updateStyle`: to update the spinner style
- `spinner.updateMessage`: to update text of a running spinner
- `spinner.succeed`, `fail`, `info`, `preserve`: mandatory to complete a line you started. each `spinner.start` needs a `spinner.succeed`, `fail` etc.. spinner after this action is done for that specific line
- Recommendation: use `spinner.print` instead of your own `writer.print` to not have non-displayed messages as spinner works on its own thread

```zig
const std = @import("std");
const zli = @import("zli");

pub fn run(ctx: zli.CommandContext) !void {
    const spinner = ctx.spinner;
    spinner.updateStyle(.{ .frames = zli.SpinnerStyles.earth, .refresh_rate_ms = 150 }); // many styles available

    // Step 1
    try spinner.start("Step 1", .{}); // New line
    std.Thread.sleep(2000 * std.time.ns_per_ms);

    try spinner.succeed("Step 1 success", .{}); // each start must be closed with succeed, fail, info, preserve

    spinner.updateStyle(.{ .frames = zli.SpinnerStyles.weather, .refresh_rate_ms = 150 }); // many styles available

    // Step 2
    try spinner.start("Step 2", .{}); // New line
    std.Thread.sleep(3000 * std.time.ns_per_ms);

    spinner.updateStyle(.{ .frames = zli.SpinnerStyles.dots, .refresh_rate_ms = 150 }); // many styles available
    try spinner.updateMessage("Step 2: Calculating things...", .{}); // update the text of step 2

    const i = work(); // do some work

    try spinner.info("Step 2 info: {d}", .{i});

    // Step 3
    try spinner.start("Step 3", .{});
    std.Thread.sleep(2000 * std.time.ns_per_ms);

    try spinner.fail("Step 3 fail", .{});

    try spinner.print("Finish\n", .{}); // instead of using ctx.writer or another writer to avoid concurrency issues
}

fn work() u128 {
    var i: u128 = 1;
    for (0..100000000) |t| {
        i = (t + i);
    }

    return i;
}
```

## ✅ Features Checklist

- [x] Commands & subcommands
- [x] Command aliases
- [x] Flags & shorthands
- [x] Type-safe flag values
- [x] Positional args (required, optional, variadic)
- [x] Named access: `ctx.getArg("name")`
- [x] Context data
- [x] Help/version auto handling
- [x] Deprecation notices
- [x] Pretty-aligned help for flags & args
- [x] Clean usage output like Cobra
- [x] Spinners and loading state (very powerful)
- [x] Persistent flags

## 📚 Documentation

See [docs](https://xcaeser.github.io/zli/) for full usage, examples, and internals.

## 📝 License

MIT. See [LICENSE](LICENSE). Contributions welcome.