https://github.com/kioz-wang/zargs
Another Comptime-argparse for Zig! Let's start to build your command line!
https://github.com/kioz-wang/zargs
argument-parser command-line positional-arguments subcommands zig zig-package ziglang
Last synced: about 2 months ago
JSON representation
Another Comptime-argparse for Zig! Let's start to build your command line!
- Host: GitHub
- URL: https://github.com/kioz-wang/zargs
- Owner: kioz-wang
- License: mit
- Created: 2025-03-04T03:10:36.000Z (2 months ago)
- Default Branch: main
- Last Pushed: 2025-03-19T04:49:48.000Z (about 2 months ago)
- Last Synced: 2025-03-19T05:27:13.977Z (about 2 months ago)
- Topics: argument-parser, command-line, positional-arguments, subcommands, zig, zig-package, ziglang
- Language: Zig
- Homepage: https://kioz-wang.github.io/zargs/
- Size: 107 KB
- Stars: 6
- Watchers: 1
- Forks: 0
- Open Issues: 6
-
Metadata Files:
- Readme: README.md
- License: LICENSE
Awesome Lists containing this project
- awesome-zig - kioz-wang/zargs - argparse for Zig. (Command Line and Argument Parser / Linker)
- awesome-zig - zargs🗒️Another Comptime-argparse for Zig
README
# zargs
> other language: [ä¸ć–‡ç®€ä˝“](README.zh-CN.md)
Another Comptime-argparse for Zig! Let's start to build your command line!
```zig
const std = @import("std");
const zargs = @import("zargs");
const Command = zargs.Command;
const Arg = zargs.Arg;
pub fn main() !void {
// Like Py3 argparse, https://docs.python.org/3.13/library/argparse.html
const remove = Command.new("remove")
.opt("verbose", u32, .{ .short = 'v' })
.optArg("count", u32, .{ .short = 'c', .argName = "CNT", .default = 9 })
.posArg("name", []const u8, .{});
// Like Rust clap, https://docs.rs/clap/latest/clap/
const cmd = Command.new("demo").requireSub("action")
.about("This is a demo intended to be showcased in the README.")
.author("KiozWang")
.homepage("https://github.com/kioz-wang/zargs")
.arg(Arg.opt("verbose", u32)
.short('v')
.help("help of verbose"))
.sub(Command.new("install")
.arg(Arg.posArg("name", []const u8))
.arg(
Arg.optArg("output", []const u8)
.short('o')
.long("out"),
))
.sub(remove);
var gpa: std.heap.GeneralPurposeAllocator(.{}) = .init;
const allocator = gpa.allocator();
const args = cmd.parse(allocator) catch |err| {
std.debug.print("Fail to parse because of {any}\n", .{err});
std.debug.print("\n{s}\n", .{cmd.usage()});
std.process.exit(1);
};
defer cmd.destroy(&args, allocator);
switch (args.action) {
.install => |a| {
std.debug.print("Installing {s}\n", .{a.name});
},
.remove => |a| {
std.debug.print("Removing {s}\n", .{a.name});
std.debug.print("{any}\n", .{a});
},
}
std.debug.print("Success to do {s}\n", .{@tagName(args.action)});
}
```
## Background
As a system level programming language, there should be an elegant solution for parsing command line arguments.
`zargs` draws inspiration from the API styles of [Py3 argparse](https://docs.python.org/3.13/library/argparse.html) and [Rust clap](https://docs.rs/clap/latest/clap/). It provides all parameter information during editing, reflects the parameter structure and parser at compile time, along with everything else needed, and supports dynamic memory allocation for parameters at runtime.
## Installation
### fetch
Get the latest version:
```bash
zig fetch --save git+https://github.com/kioz-wang/zargs
```
To fetch a specific version (e.g., `v0.14.3`):
```bash
zig fetch --save https://github.com/kioz-wang/zargs/archive/refs/tags/v0.14.3.tar.gz
```
#### Version Notes
> See https://github.com/kioz-wang/zargs/releases
The version number follows the format `vx.y.z`:
- **x**: Currently fixed at 0. It will increment to 1 when the project stabilizes. Afterward, it will increment by 1 for any breaking changes.
- **y**: Represents the supported Zig version. For example, `vx.14.z` supports [Zig 0.14.0](https://github.com/ziglang/zig/releases/tag/0.14.0).
- **z**: Iteration version, where even numbers indicate releases with new features or significant changes (see [milestones](https://github.com/kioz-wang/zargs/milestones)), and odd numbers indicate releases with fixes or minor changes.
### import
Use `addImport` in your `build.zig` (e.g.):
```zig
const exe = b.addExecutable(.{
.name = "your_app",
.root_source_file = b.path("src/main.zig"),
.target = b.standardTargetOptions(.{}),
.optimize = b.standardOptimizeOption(.{}),
});
exe.root_module.addImport("zargs", b.dependency("zargs", .{}).module("zargs"));
b.installArtifact(exe);
const run_cmd = b.addRunArtifact(exe);
run_cmd.step.dependOn(b.getInstallStep());
if (b.args) |args| {
run_cmd.addArgs(args);
}
const run_step = b.step("run", "Run the app");
run_step.dependOn(&run_cmd.step);
```
After importing the `zargs`, you will obtain the iterator (`TokenIter`), command builder (`Command`), and universal parsing function (`parseAny`):
```zig
const zargs = @import("zargs");
```
> For more information and usage details about these three powerful tools, please refer to the [documentation](#APIs).
## Features
### Options, Arguments, Subcommands
#### Terminology
- Option (`opt`)
- Single Option (`singleOpt`)
- Boolean Option (`boolOpt`), `T == bool`
- Accumulative Option (`repeatOpt`), `@typeInfo(T) == .int`
- Option with Argument (`argOpt`)
- Option with Single Argument (`singleArgOpt`), T
- Option with Fixed Number of Arguments (`arrayArgOpt`), `[n]T`
- Option with Variable Number of Arguments (`multiArgOpt`), `[]T`
- Argument (`arg`)
- Option Argument (`optArg`) (equivalent to Option with Argument)
- Positional Argument (`posArg`)
- Single Positional Argument (`singlePosArg`), T
- Fixed Number of Positional Arguments (`arrayPosArg`), `[n]T`
- Subcommand (`subCmd`)
#### Matching and Parsing
Matching and parsing are driven by an iterator. For options, the option is always matched first, and if it takes an argument, the argument is then parsed. For positional arguments, parsing is attempted directly.
For arguments, T must be the smallest parsable unit: `[]const u8` -> T
- `.int`
- `.float`
- `.bool`
- `.enum`: By default, `std.meta.stringToEnum` is used, but the parse method takes precedence.
- `.struct`: A struct with a parse method.
If T is not parsable, a custom parser (`.parseFn`) can be defined for the argument. Obviously, a parser cannot be configured for a single option, as it would be meaningless.
#### Default Values and Optionality
Options and arguments can be configured with default values (`.default`). Once configured, the option or argument becomes optional.
Even if not explicitly configured, single options always have default values: boolean options default to `false`, and accumulative options default to `0`. Therefore, single options are always optional.
#### Callbacks
A callback (`.callBackFn`) can be configured, which will be executed after matching and parsing.
#### Subcommands
A command cannot have both positional arguments and subcommands simultaneously.
#### Representation
For the parser, except for accumulative options and options with a variable number of arguments, no option can appear more than once.
Various representations are primarily supported by the iterator.
Options are further divided into short options and long options:
- **Short Option**: `-v`
- **Long Option**: `--verbose`
Options with a single argument can use a connector to link the option and the argument:
- **Short Option**: `-o=hello`, `-o hello`
- **Long Option**: `--output=hello`, `--output hello`
> Dropping the connector or whitespace for short options is not allowed, as it results in poor readability!
For options with a fixed number of arguments, connectors cannot be used, and all arguments must be provided at once. For example, with a long option:
```bash
--files f0 f1 f2 # [3]const T
```
Options with a variable number of arguments are similar to options with a single argument but can appear multiple times, e.g.:
```bash
--file f0 -v --file=f1 --greet # []const T
```
Multiple short options can share a prefix, but if an option takes an argument, it must be placed last, e.g.:
```bash
-Rns
-Rnso hello
-Rnso=hello
```
Once a positional argument appears, the parser informs the iterator to only return positional arguments, even if the arguments might have an option prefix, e.g.:
```bash
-o hello a b -v # -o is an option with a single argument, so a, b, -v are all positional arguments
```
An option terminator can be used to inform the iterator to only return positional arguments, e.g.:
```bash
--output hello -- a b -v
```
Double quotes can be used to avoid iterator ambiguity, e.g., to pass a negative number `-1`, double quotes must be used:
```bash
--num \"-1\"
```
> Since the shell removes double quotes, escape characters are also required! If a connector is used, escaping is unnecessary: `--num="-1"`.
### Compile-Time Command Construction
As shown in the example at the beginning of the article, command construction can be completed in a single line of code through chaining.
#### CallBackFn for Command
```zig
comptime cmd.callBack(struct {
const C = cmd;
fn f(_: *C.Result()) void {
std.debug.print("CallBack of {s}\n", .{ C.name });
}
}.f);
```
### Compile-Time Parser Generation
```zig
const args = try cmd.parse(allocator);
defer cmd.destroy(&args, allocator);
```
Simply call `parse` to generate the parser and argument structure. This method internally creates a system iterator, which is destroyed after use.
Additionally, `parseFrom` supports passing a custom iterator and optionally avoids using a memory allocator. If no allocator is used, there is no need to defer destroy.
#### Retrieving Remaining Command-Line Arguments
When the parser has completed its task, if you still need to handle the remaining arguments manually, you can call the iterator's `nextAllBase` method.
If further parsing of the arguments is required, you can use the `parseAny` function.
#### Versatile iterators
Flexible for real and test scenarios
- System iterator (`init`): get real command line arguments.
- General iterator (`initGeneral`): splits command line arguments from a one-line string.
- Line iterator (`initLine`): same as regular iterator, but you can specify delimiters.
- List iterator (`initList`): iterates over a list of strings.
Short option prefixes (`-`), long option prefixes (`--`), connectors (`=`), option terminators (`--`) can be customized for iterators (see [presentation](#presentation) for usage scenarios).
### Compile-Time Usage and Help Generation
```zig
_ = cmd.usage();
_ = cmd.help();
```
## APIs
See https://kioz-wang.github.io/zargs/#doc.command.Command
## Examples
### builtin
> Look at [here](examples/)
To build all examples:
```bash
zig build examples
```
To list all examples (all step prefixed `ex-` are examples):
```bash
zig build -l
```
To execute an example:
```bash
zig build ex-01.add -- -h
```
### more
> Welcome to submit PRs to link your project that use `zargs`!
More real-world examples are coming!
- [filepacker](https://github.com/kioz-wang/filepacker/blob/master/src/main.zig)
## License
[MIT](LICENSE) © Kioz Wang