guile-config: Command --help is not displayed when there are required arguments

[sirgazil]

Hi,

When using "guile-config" for declaring my CLIs I've noticed that if I define 
an argument as non-optional for a command, then trying to display the --help of 
that command fails. 

Consider the following script which displays "What yummy apple!" when it's run 
like "$ eat apple":


#+BEGIN_SRC scheme
(use-modules (config)
             (config api)
             (ice-9 format)
             (ice-9 match))


;;; CONSTANTS
;;; =========

(define FRUITS
  (list "apple" "banana" "kiwi" "mango"))



;;; VALIDATORS
;;; ==========

(define (fruit? fruit)
  (member fruit FRUITS))



;;; ARGUMENTS AND OPTIONS
;;; =====================

(define fruit
  (argument (name 'fruit)
            (synopsis "The name of a fruit.")
            (example "apple")
            (optional? #false)
            (test fruit?)))



;;; CLI SPECIFICATION
;;; =================

(define spec
  (configuration
   (name 'eat)
   (synopsis "Eat imaginary fruits.")
   (version "1.0")
   (arguments (list fruit))))



;;; CLI DISPATCHER
;;; ==============

(define (dispatcher command spec)
  #| Execute the appropriate procedure for the given COMMAND if it is
  part of the given command-line interface specification.

  COMMAND (list of strings)
    A list of strings that represent a command-line instruction passed
    to the program (see the Guile command-line procedure).

  SPEC (Configuration)
    A <configuration> record as specified by the guile-config library
    specifying the command-line interface of the program.

  RESULT
    Execute the COMMAND or display help information if the COMMAND is
    not recognized. |#
  (let* ((options (getopt-config-auto command spec))
         (fruit (option-ref options '(fruit))))
    (catch 'match-error
      (lambda ()
        (match (full-command options)
          ((_) (format #true "What yummy ~a!!~%" fruit))))

      (lambda (. args)
        (begin (display "ERROR: Command not found.")
               (newline) (newline)
               (emit-help options))))))



;;; RUN
;;; ===

(dispatcher (command-line) spec)

#+END_SRC


Now, when I try to display the help information of the "eat" command, I get 
this message:


#+BEGIN_EXAMPLE
$ eat --help
error: eat: argument must be specified: fruit
Usage: eat 

Options:
#+END_EXAMPLE


Is this a bug or am I doing something wrong?


---
https://sirgazil.bitbucket.io/