Please add cl-argparse

[simkoc]

https://github.com/simkoc/cl-argparse

This library provides the functionality of a python-esque command line parser.

[quicklisp]

How does this improve upon or differ from the many existing argument parsing libraries in Quicklisp?

[Hexstream]

A fair question. We are again confronted with the Discoverability Problem.

Here is a (probably partial) list of libraries in this category.

[simkoc]

This is a fair question.

I really liked the functionality of python argparse to allow for subparsers based on keywords in the command line as well as positional, optional, and flags.

Subparsers:

./program action-name [parameters...]
./program different-action-name [different-parameter...]

Positionals

./program arg-pos-1 arg-pos-2

Those can be infinitely boxed (i.e., unlimited subparsers) and, thus, each sub-parser can have its own optionals and positionals as well as further sub parsers. As far as I was able to see none of the already existing parsers supported such behavior or it was not easily accessible/noticeable.

My solution is supposed to fill this perceived gap.

[simkoc]

I extended the given example in the README.md to clear things up a bit:

This source code

(in-package :cl-argparse)

#here the parser is created, can be separated into multiple functions if required
(defun create-parser ()
  (create-main-parser (main-parser "here comes the description of the program")
    (add-flag main-parser :short "g" :long "goo" :help "this is an example flag" :var "goo")
    (add-optional main-parser :short "t" :long "test" :help "this is an example optional argument" :var "test")
    (add-positional main-parser :name "pos" :help "this is an example for a positional")
    (add-subparser main-parser (create-sub-parser (sub "this is a sub action parser")
                                 (add-positional sub :name "action" :help "this is an example for a positional")))
    (add-subparser main-parser (create-sub-parser (sub-2 "this is the second sub parser")
                                 (add-positional sub-2 :name "sub-2-action" :help "this is an example for a different action in a different subparser")))))

# print the auto generated help message for the main parser
(parse (create-parser) (list "-h"))

# print the auto generated help message for the sub parser sub
(parse (create-parser) (list "positional-value" "sub" "-h"))

# print the auto generated help message for the sub parser sub-2
(parse (create-parser) (list "positional-value" "sub-2" "-h"))

# print the parsed values after giving all parameters including for the sub parser sub
(format t "~a~%"
        (parse (create-parser) (list "-g" "-t" "alle" "positional" "sub" "theaction")))

# print the parsed values after giving all parameters including for the sub parser sub-2 
(format t "~a~%"
        (parse (create-parser) (list "-g" "-t" "alle" "positional" "sub-2" "theaction")))

Generates the following output

./program.lisp  (-g,-h,-t) [pos] {sub-2,sub}

here comes the description of the program

   -g/--goo this is an example flag
   -h/--help displays this help message
   -t/--test this is an example optional argument
   [pos] this is an example for a positional
./program.lisp ... sub (-h) [action]

this is a sub action parser

   -h/--help displays this help message
   [action] this is an example for a positional
./program.lisp ... sub-2 (-h) [sub-2-action]

this is the second sub parser

   -h/--help displays this help message
   [sub-2-action] this is an example for a different action in a different subparser
<PARSER
goo -> T
test -> alle
pos -> positional
action -> theaction
>
<PARSER
goo -> T
test -> alle
pos -> positional
sub-2-action -> theaction
>

[quicklisp]

Failure log here: http://report.quicklisp.org/2019-12-26/failure-report/cl-argparse.html

[simkoc]

Sorry my bad. I forgot to add that required attribute with the others. Should now be fixed.