clap4shell 0.1.3

clap4shell: standalone clap wrapper for shell scripts

clap4shell is a replacement for getopt based on clap.

clap4shell takes option descriptors as a YAML document from stdin, then prints the parsed result in newline-delimited key=value format which can be eval'd. See example.sh for concrete usage.

Installation

nix profile install github:fumieval/clap4shell

Usage

Configurations look like

name: example
bin_name: $0
version: "1.0"
about: sample text
author: Fumiaki Kinoshita <fumiexcel@gmail.com>
# Flags take no arguments.
# Number of occurences will be reported (e.g. verbose=1)
flags:
  verbose:
    help: verbose output
    short: v
    long: verbose
# Options arguments are collected as newline-separated list of values.
opts:
  # usage syntax is also supported
  # cf. https://docs.rs/clap/2.33.0/clap/struct.Arg.html#syntax
  host: -h --host <HOST> 'host name'
  mode:
    long: mode
    help: option with a certain set of possible values
    possible_values: [ herbivore, carnivore, omnivore ]
# Positional arguments
args:
  - name: cmd
    help: command
    required: true
  - name: arg
    help: command arguments
    multiple: true
subcommands:
  ls: #The name will be assigned to $subcommand
    about: Display a list of entities
    args:
    - name: name
      multiple: true

The typical usage is to embed option definitions in a shell heredoc, pass all arguments to clap4shell and eval its output:

eval "$(clap4shell parse "$@" <<EOT
...
EOT
)"

Completion

clap4shell-completion <shell> -o <path> subcommand generates an autocompletion script and writes the script to path.

clap4shell clap4shell-completion bash -o ./bash-completion.sh < definition.yaml

Note that clap does not support completion for subcommands yet (clap panics for some reason)

Notes

I intentionally avoided using clap::App::from_yaml because the redundancy of the YAML representation and difficulty of debugging panics. The YAML interface is being deprecated: https://github.com/clap-rs/clap/issues/3087