Question

Using tools.cli, how can I can I create a non-optional argument with optional ones?

I have a function

(defn parse-opts
  [args]
  (cli args
  ["-f" "--ifn" "input file"]
 (optional ["-o" "--outp" ".csv pipe delimited output file" 
      :default "assess_pro_out.csv"] identity)
 (optional ["-d" "--debug" "Debug flag for logging." :default 0 
      :parse-fn #(Integer. %)])))

that compiles but produces

Exception in thread "main" clojure.lang.ArityException: 
Wrong number of args (2) passed to: PersistentVector

when I run my main program without arguments.

If this option is made like the rest

(optional ["-f" "--ifn" "input file"] identity)

everything works fine.

I just want one parameter to be non-optional. What am I doing wrong?

I do have a workaround for this, but I’d still like to know if it is okay to mix optional and non-optional arguments to cli.

(defn -main 
[& args]
(let [opts (parse-opts args)
      start-time (str (Date.))
      parsed-csv-data (if-not (:ifn opts)
                       (do
                       (println "Usage: assess-chk [-f -ifn] input-file-name")
                       (System/exit -2))
                       (utl/fetch-csv-data (:ifn opts)))

Thanks.

Answer 1

You’re using an old version of tools.cli (probably v0.1.0). For that version it appears that you should use (required ...) for required options. See the docs at https://github.com/clojure/tools.cli/tree/a741b23f230123179fc518af772f1c057058f7d2

In the current version of tools.cli, options are always optional and the optional and required functions are removed.