Re: tools.cli and required arguments

[guns]

On Wed 22 Jan 2014 at 01:48:22PM +0100, Alf Kristian Støyle wrote:

> From the documentation it seems that specifying the second part of the
> "long option" should be enough to make an argument required. So this
> minimal example should also produce errors:
>
> (def cli-options-simplified
>   [["-p" "--port PORT" "Port number"]])
> ;=> (var user/cli-options-simplified)
>
> (:errors (parse-opts [] cli-options-simplified))
> ;=> nil
>
> So what are we misunderstanding? Any pointers would be greatly appreciated.
>
> Using Clojure 1.5.1 with tools.cli 0.3.1.

Hi Alf,

An option with a required argument (via "--port PORT" or the :required
entry) only specifies that the option must be followed by an argument
_if_ it is specified on the command line. For example,

    $ cmd --port

is an error, but simply

    $ cmd

is not.

If you would like require that --port must be specified in every
invocation, you can assert its existence/value in the options map:

    (let [{:keys [options errors …]} (parse-opts argv cli-options)]
      …
      (assert (:port options) "`--port` must be specified")
      …)

You can, of course, set a :default value for a required option.

    HTH
    guns

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