Getting command line arguments in Common Lisp

Question

How can I get the command line arguments in (specifically in GNU, if there are any differences) Common Lisp?

Inkling

For next googlers: there's the mentioned CLON library, now also the simpler unix-opts, and a tutorial. – Yaupon

Answer 1

I'm assuming that you are scripting with CLisp. You can create a file containing

#! /usr/local/bin/clisp
(format t "~&~S~&" *args*)

Make it executable by running

$ chmod 755 <filename>

Running it gives

$ ./<filename>
NIL
$ ./<filename> a b c
("a" "b" "c")
$ ./<filename> "a b c" 1 2 3
("a b c" "1" "2" "3")

Unintelligible

the link in this post is no longer viable. :( – Calva

this is super cool. but how can i make data from the strings? my function is used to inputs like this (unique '(a b c c d d d e f)) and it doesn't work with strings :O .. i tried to (mapcar #'make-symbol args) but that doesn't seem to do the job – Harim

Answer 2

http://cl-cookbook.sourceforge.net/os.html provides some insight

  (defun my-command-line ()
  (or 
   #+CLISP *args*
   #+SBCL *posix-argv*  
   #+LISPWORKS system:*line-arguments-list*
   #+CMU extensions:*command-line-words*
   nil))

is what you are looking for, I think.

(edit): see the newer Cookbook: https://lispcookbook.github.io/cl-cookbook/scripting.html

Pinfish

(or FOO nil) is equivalent to FOO, is it not? – Cynth

Yes, but when you have your FOO conditionally read, it's, possibly, good to have a fall-back. But, then, the value of (or) is, not entirely surprising, NIL (just as the value of (and) is T). – Duyne

For some reason this doesn't work for clisp for me: *** - OR: variable *ARGS* has no value – Crinose

Answer 3

Are you talking about Clisp or GCL? Seems like in GCL the command line arguments get passed in si::*command-args*.

Philomena

Answer 4

In SBCL,we can use sb-ext:*posix-argv* to get the argv from a Common Lisp script. sb-ext:*posix-argv* is a list holding all the arguments, the first member of the list is the script filename.

Elide

I'm not sure this works anymore. I get the error message 'Symbol "POSIX-ARGV" not found in the SB-EXT package.' – Ephrayim

should be sb-ext:*posix-argv*, in the old text, the *something* worked as a style. I'm sorry. – Elide

Answer 5

A portable way is uiop:command-line-arguments (available in ASDF3, shipped by default in all major implementations).

Libraries-wise, there is the mentioned Clon library that abstracts mechanisms for each implementation, and now also the simpler unix-opts, and a tutorial on the Cookbook.

(ql:quickload "unix-opts")

(opts:define-opts
    (:name :help
       :description "print this help text"
       :short #\h
       :long "help")
    (:name :nb
       :description "here we want a number argument"
       :short #\n
       :long "nb"
       :arg-parser #'parse-integer) ;; <- takes an argument
    (:name :info
       :description "info"
       :short #\i
       :long "info"))

Then actual parsing is done with (opts:get-opts), which returns two values: the options, and the remaining free arguments.

Yaupon

Answer 6

As seen in https://mcmap.net/q/556807/-getting-command-line-arguments-in-common-lisp, each implementation has its own mechanism. The usual way to deal with this is to use a wrapper library that presents a unified interface to you.

Such a library can provide further assistance in not only reading things in, but also converting them and giving helpful output to the user. A quite complete package is CLON (not to be confused with CLON or CLON, sorry), the Command Line Options Nuker, which also brings extensive documentation. There are others, though, should your needs be more lightweight, for example, command-line-arguments and apply-argv.

The packages in quicklisp for these are named net.didierverna.clon, command-line-arguments, and apply-argv, respectively.

Seamanship

Answer 7

Just go for it on SBCL (2.1.11.debian):

(defun main ()
    (let (
        (args sb-ext:*posix-argv*))

    (format t "args = ~a~%" args)))

(main)

Chromogen