argp is a Go library providing a GNU-style command-line argument parser. It supports features like short and long options, flags, subcommands, required arguments, default values, and generating help text automatically. The library aims for flexibility and correctness while striving for good performance and minimal dependencies. It emphasizes handling POSIX-style argument conventions and provides a simple, declarative API for defining command-line interfaces within Go applications.
The GitHub repository argp, created by Tom de Wolff, introduces a Go package that provides a command-line argument parser mimicking the style and functionality of GNU's argp library. This allows developers familiar with the GNU argument parsing conventions to easily implement similar behavior in their Go programs. The package aims to be a robust and feature-rich solution for handling command-line input.
Key features of this Go implementation include support for both short and long options, with automatic generation of help text. It handles various argument types such as flags (boolean), options with associated values (strings, integers, etc.), positional arguments, and subcommands. The parser can be customized extensively to enforce required arguments, define default values, specify valid ranges for numeric arguments, and provide detailed usage instructions.
The argp package uses a declarative approach, allowing developers to define the command-line interface through structs and struct tags. This approach promotes clarity and makes it easier to manage complex argument structures. Functions are provided to parse the command-line arguments and populate the corresponding struct fields. Error handling is integrated, providing informative messages to the user in case of invalid input.
The package aims for high performance and strives to be a reliable and efficient solution for parsing command-line arguments in Go applications. The documentation within the repository provides detailed explanations and examples of usage, covering various scenarios and demonstrating how to leverage the package's capabilities. It also outlines how to handle different argument types, define subcommands, and customize the generated help text. The project maintains a focus on adhering to the established GNU argp conventions, ensuring a familiar experience for developers accustomed to that style of argument parsing.
Summary of Comments ( 18 )
https://news.ycombinator.com/item?id=43452525
Hacker News users discussed
argp's performance, ease of use, and its similarity to the C library it emulates. Several commenters appreciated the library's speed and small size, finding it a preferable alternative to more complex Go flag parsing libraries likepflag. However, some debated the value of mimicking the GNU style in Go, questioning its ergonomic fit. One user highlighted potential issues with error handling and suggested improvements. Others expressed concerns about compatibility and long-term maintenance. The general sentiment leaned towards cautious optimism, acknowledgingargp's strengths while also raising valid concerns.The Hacker News post about
argp, a GNU-style command line argument parser for Go, has several comments discussing its merits and drawbacks.One commenter points out that while they appreciate the effort, they generally prefer using Go's
flagpackage for simpler cases and moving to a more powerful library likespf13/cobrawhen the needs become more complex. They feelargpsits in an awkward middle ground. This sentiment is echoed by another user who adds thatcobraalso handles things like help text generation and subcommand management effectively, making it a more complete solution.Another commenter expresses concern over the dependency on C code, viewing it as a potential disadvantage. They also question the long-term maintenance of the project and suggest exploring pure Go alternatives.
Several users discuss the specific GNU style of argument parsing, with some appreciating its familiarity and others finding it overly complex and verbose. One commenter specifically mentions the lack of positional argument support as a drawback, preferring libraries that offer more flexibility in this area.
There's a discussion about the "batteries included" philosophy of Go and whether a project like
argpfits into that ecosystem. Some argue that the standard library'sflagpackage is sufficient for most use cases, while others appreciate the availability of external libraries likeargpfor those who prefer a different style.One commenter mentions that while they're not currently using
argp, they're keeping an eye on it for future projects, particularly those that require close compatibility with existing C codebases.Finally, the author of
argpchimes in to clarify some points. They explain that the library aims to provide a familiar experience for developers coming from a C/GNU background and addresses the concerns about C dependencies, stating they're minimal and primarily for parsing GNU-style options. They also acknowledge the existence of other argument parsers but emphasize thatargpfills a specific niche for those who prefer the GNU conventions. They further explain that POSIX-compliant short and long option parsing is available, but GNU extensions are the project's focus. They acknowledge positional arguments are currently missing and are open to considering them for the future. The author also details their motivation: they needed GNU-style parsing in a project and, unhappy with existing Go options, createdargpand subsequently open-sourced it.