ohmyzsh/plugins/getgb/getgb.plugin.zsh

function _gb_commands() {
    local ret=1 state
    _arguments -C ':command:->command' '*::options:->options' && ret=0

    case $state in
      (command)

        local -a subcommands
        subcommands=(
          "build:build a package"
          "doc:show documentation for a package or symbol"
          "env:print project environment variables"
          "generate:generate Go files by processing source"
          "help:displays the help"
          "info:info returns information about this project"
          "list:list the packages named by the importpaths"
          "test:test packages"
          "vendor:manage your vendored dependencies"
        )
        _describe -t subcommands 'gb subcommands' subcommands && ret=0
      ;;

      (options)
        case $line[1] in
          (build)
            _arguments \
              -f'[ignore cached packages]' \
              -F'[do not cache packages]' \
              -q'[decreases verbosity]' \
              -P'[the number of build jobs to run in parallel]' \
              -R'[sets the base of the project root search path]' \
              -dotfile'[output a dot formatted file of the build steps]' \
              -ldflags'["flag list" arguments to pass to the linker]' \
              -gcflags'["arg list" arguments to pass to the compiler]' \
              -race'[enable data race detection]' \
              -tags'["tag list" additional build tags]'
            ;;
          (list)
            _arguments \
              -f'[alternate format for the list, using the syntax of package template]' \
              -s'[read format template from STDIN]' \
              -json'[prints output in structured JSON format]'
            ;;
          (test)
            _arguments \
              -v'[print output from test subprocess]' \
              -ldflags'["flag list" arguments to pass to the linker]' \
              -gcflags'["arg list" arguments to pass to the compiler]' \
              -race'[enable data race detection]' \
              -tags'["tag list" additional build tags]'
            ;;
          (vendor)
            __gb-vendor
        esac
      ;;
    esac

    return ret
}

compdef _gb_commands gb

__gb-vendor ()
{
  local curcontext="$curcontext" state line

  _arguments -C ':command:->command' '*::options:->options'

	case $state in
		(command)

			local -a subcommands
			subcommands=(
				'delete:deletes a local dependency'
				'fetch:fetch a remote dependency'
				'list:lists dependencies, one per line'
        'purge:remove all unreferenced dependencies'
				'restore:restore dependencies from the manifest'
				'update:update a local dependency'
			)
			_describe -t subcommands 'gb vendor subcommands' subcommands && ret=0
		;;

		(options)
			case $line[1] in
				(delete)
					_arguments \
						-all'[remove all dependencies]'
				  ;;
        (fetch)
          _arguments \
            -branch'[fetch from a particular branch]' \
            -no-recurse'[do not fetch recursively]' \
            -tag'[fetch the specified tag]' \
            -revision'[fetch the specific revision from the branch (if supplied)]' \
            -precaire'[allow the use of insecure protocols]' \
          ;;
        (list)
          _arguments \
            -f'[controls the template used for printing each manifest entry]'
          ;;
        (restore)
          _arguments \
            -precaire'[allow the use of insecure protocols]'
          ;;
        (update)
          _arguments \
            -all'[update all dependencies in the manifest or supply a given dependency]' \
            -precaire'[allow the use of insecure protocols]'
          ;;
			esac
		;;
	esac
}