tools.cli is a command line argument parser for Clojure.
(cli args
["-p" "--port" "Listen on this port" :parse-fn #(Integer. %)]
["-h" "--host" "The hostname" :default "localhost"]
["-v" "--[no-]verbose" :default true]
["-l" "--log-directory" :default "/some/path"])
with args of:
["-p" "8080"
"--no-verbose"
"--log-directory" "/tmp"
"some-file"]
will produce a vector containing three elements:
a clojure map with the names picked out for you as keywords:
{:port 8080
:host "localhost"
:verbose false
:log-directory "/tmp"}
a vector of trailing arguments that are not options:
["some-file"]
and a documentation string to use to provide help:
"Usage:
Switches Default Desc
-------- ------- ----
-p, --port Listen on this port
-h, --host localhost The hostname
-v, --no-verbose --verbose true
-l, --log-directory /some/path
An option is specified by providing a vector of information:
Switches should be provided first, from least to most specific. The last switch you provide will be used as the name for the argument in the resulting hash-map. The following:
["-p" "--port"]
defines an argument with two possible switches, the name of which will be :port in the resulting hash-map.
Next is an optional doc string:
["-p" "--port" "The port to listen on"]
This will be printed in the 'Desc' column of the help banner.
Following that are optional parameters, provided in key-value pairs:
["-p" "--port" "The port to listen on" :default 8080 :parse-fn #(Integer. %)]
These should be self-explanatory. The defaults if not provided are as follows:
{:default nil
:parse-fn identity
:flag false}
Flags are indicated either through naming convention:
["-v" "--[no-]verbose" "Be chatty"]
(note the [no-] in the argument name).
Or you can explicitly mark them as flags:
["-v" "--verbose" "Be chatty" :flag true]
Either way, when providing them on the command line, using the name itself will set to true, and using the name prefixed with 'no-' will set the argument to false:
(cli ["-v"]
["-v" "--[no-]verbose"])
=> [{:verbose true}, ...]
(cli ["--no-verbose"]
["-v" "--[no-]verbose"])
=> [{:verbose false}, ...]
Note: there is no short-form to set the flag to false (-no-v will not work!).
Any trailing arguments given to cli are returned as the second item
in the resulting vector:
(cli ["--port" "9999" "some" "extra" "arguments"]
["--port" :parse-fn #(Integer. %)])
=> [{:port 9999}, ["some" "extra" "arguments"], ...]
This allows you to deal with parameters such as filenames which are commonly provided at the end of an argument list.
If you with to explicitly signal the end of arguments, you can use a double-hyphen:
(cli ["--port" "9999" "--" "some" "--extra" "arguments"]
["--port" :parse-fn #(Integer. %)])
=> [{:port 9999}, ["some" "--extra" "arguments"], ...]
This is useful when your extra arguments look like switches.
The third item in the resulting vector is a banner useful for providing help to the user:
(let [[options args banner] (cli ["--faux" "bar"]
["-h" "--help" "Show help" :default false :flag true]
["-f" "--faux" "The faux du fafa"])]
(when (:help options)
(println banner)
(System/exit 0))
(println options))
Copyright (c) Rich Hickey and contributors. All rights reserved.
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