Thank you, I haven't heard of that one before. However, all the examples look like it gets called as an external library, which would either need to be distributed with a script, or to already be installed by a user.

Is there a feature I'm not seeing that would generate an argument parser without external dependencies?

Yes, arguments::generate_parser function. Install bash-modules, then run `. import.sh log arguments`, then call `arguments::generate_parser '--foo)FOO;String'` , and it will generate function with parser, which include parser for foo option for both `--foo VALUE` and `--foo=VALUE`:

  ...
  
        --foo)
          FOO="${2:?ERROR: String value is required for \"-f|--foo\" option. See --help for details.}"
          shift 2
        ;;
        --foo=*)
          FOO="${1#*=}"
          shift 1
        ;;
  ...