https://github.com/rbardou/clap

Command-Line Argument Parsing, imperative style with a consumption mechanism.
https://github.com/rbardou/clap

Last synced: about 2 months ago
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Command-Line Argument Parsing, imperative style with a consumption mechanism.

• Host: GitHub
• URL: https://github.com/rbardou/clap
• Owner: rbardou
• License: mit
• Created: 2020-09-27T12:48:40.000Z (about 4 years ago)
• Default Branch: master
• Last Pushed: 2023-03-26T08:33:14.000Z (over 1 year ago)
• Last Synced: 2024-08-02T07:17:35.890Z (5 months ago)
• Language: OCaml
• Size: 40 KB
• Stars: 25
• Watchers: 2
• Forks: 0
• Open Issues: 2
• Metadata Files:
  • Readme: README.md
  • Changelog: CHANGES.md
  • License: LICENSE

Awesome Lists containing this project

• awesome-cli-frameworks - clap - Line Argument Parsing, imperative style with a consumption mechanism. ([Ocaml](https://ocaml.org/) / Useful awesome list for Go cli)

README

        
# Clap: Command-Line Argument Parsing

Clap is a library for command-line argument parsing.

Clap works by directly consuming arguments in an imperative way.

Traditionally, argument parsing in OCaml is done by first defining

a specification (an OCaml value defining the types of arguments),

and then parsing from this specification.

The "impure" approach of Clap skips the need to define a specification

and results in code which is quite simple in practice,

with limited boilerplate.

Clap does construct a specification internally as arguments are parsed.

It uses it to generate the `--help`, following usual man page conventions.

## Installation

Clap is available as an opam package:

    opam install clap

To use it, add `clap` as a dependency in your `dune` file.

## API Documentation

See [src/clap.mli](src/clap.mli).

## Example

See [demo/demo.ml](demo/demo.ml).

## The Two Rules

One limitation of Clap is that you have to follow two rules which are not enforced

by typing:

- read named arguments before unnamed arguments;

- call `Clap.close` before actually using arguments.

There are exceptions to these rules.

- You can read a named argument after an unnamed argument if you are ok that

  the named argument cannot appear before the unnamed argument.

  For instance, if the unnamed argument is a subcommand name and the named argument

  only exists for this subcommand, you can read the command name first and then

  decide whether or not to read the named argument. Users will not be able to

  specify the named argument before the command name but this behavior is usually ok

  for subcommands.

- If an argument cannot be invalid, i.e. it is not mandatory and all strings

  are valid values for it, then you can use its value before calling `Clap.close`.