rutledgepaulv / cli

What

A CLI parsing library offering out-of-the-box support for command hierarchies, middleware, option validation / parsing, positional argument validation / parsing, and automatic help generation.

This library does not wrap tools.cli and instead implements its own command parsing from scratch.

This library does not use clojure.spec for option validation and instead uses Malli.

Why

I love Malli; I value middleware and command hierarchies; and users want good error messages.

Example Usage

(require '[io.github.rutledgepaulv.cli.core :as cli])

(def AddCommand
  {:command     "add"
   :run         (fn [{:keys [a b]}] (+ a b))
   :description "Adds two numbers together."
   :options     {:a {:description "The first number to add."
                     :parser      :number
                     :aliases     #{"-a" "--alpha"}
                     :schema      [:and :int [:fn {:error/message "must be greater than 0"} pos?]]}
                 :b {:description "The second number to add."
                     :parser      :number
                     :aliases     #{"-b" "--beta"}
                     :schema      [:and :int [:fn {:error/message "must be greater than 0"} pos?]]}}})

(def MathCommand
  {:command     "math"
   :description "This is the math command."
   :subcommands #{AddCommand}})

(def MainCommand
  {:command     "main"
   :description "This is the main command."
   :middleware  (fn middleware [handler outer-options]
                  (fn new-handler [inner-options]
                    (let [start-time (System/currentTimeMillis)
                          response   (handler (merge outer-options inner-options))
                          stop-time  (System/currentTimeMillis)]
                      (println "command took: " (- stop-time start-time) "milliseconds")
                      response)))
   :subcommands #{MathCommand}})

; if you already have parsed arguments from a shell (like inside -main)
(cli/run MainCommand ["main" "math" "add" "-a" "1" "-b" "2"])

; if you want to pass a single string and simulate the parsing done by a shell
(cli/run-string MainCommand "main math add -a 1 -b 2")

; help subcommands are implemented for you on 'branch' commands
(cli/run-string MainCommand "main help")

; help flags are implemented for you on 'leaf' commands
(cli/run-string MainCommand "main math add -h")

; you can show the entire command tree at once
(cli/run-string MainCommand "main tree")

cli's Issues

add "did you mean?" typo assistance