parse-arg.clj

;; Based on https://clojuredocs.org/clojure.core/condp#example-542692cbc026201cdc326bea

(defn parse-arg [s]
  (condp (comp next re-matches) s
    #"([+-])(\w+)" :>> (fn [[f k]] [(keyword k) (= f "+")])
    #"(\w+)=(\w+)" :>> (fn [[k v]] [(keyword k) v])
    (throw (IllegalArgumentException. s))))
  
(parse-arg "+foo")    ;=> [:foo true]
(parse-arg "-foo")    ;=> [:foo false]
(parse-arg "foo=bar") ;=> [:foo "bar"]

(->> ["+foo" "-bar" "baz=quuz"]
     (map parse-arg)
     (into {}))       ;=> {:foo true, :bar false, :baz "quuz"}