Subject: Re: bug#21698: accessing multiple flagged values with (ice-9 getopt-long)

From: Andy Wingo <[email-masked]>
Date: Fri, 24 Jun 2016 16:53:46 +0200

Hi Matt,

Thanks for the patch.  My instinct however is to point you towards
SRFI-37, which in addition to supporting multiple argument values can
also be used to fold over the precise argument order.  I just don't know
that we should be expanding (ice-9 getopt-long); it has its use case and
if your needs go beyond it, then probably your needs go way beyond it.

  https://www.gnu.org/software/guile/manual/html_node/SRFI_002d37.html

Ludovic, second opinions?

Andy

On Sat 17 Oct 2015 19:05, Matt Wette <[email-masked]> writes:

> This is in reference to guile-2.0.11.
>
> The (ice-9 getopt-long) module does not provide a process for
> accessing multiple command line arguments.
>
> A patch for ice-9/getopt-long.scm is attached which adds the procedure
> getopt-ref/many to access multiple argument values.
>
> The following program and results illustrate the use of the current
> getopt-ref and the proposed getopt-ref/many:
>
> mwette$ ./gotest.scm -f foo1 -b bar1 -f foo2 baz1 baz2
>
> program arguments:
>
> ("./gotest.scm" "-f" "foo1" "-b" "bar1" "-f" "foo2" "baz1" "baz2")
>
> getopt using option-ref:
>
> foo: "foo2"
>
> bar: "bar1"
>
> getopt using option-ref/many:
>
> foo: ("foo1" "foo2")
>
> bar: "bar1"
>
> where
>
> mwette$ cat gotest.scm 
>
> #!/opt/local/bin/guile
>
> !#
>
> (use-modules (ice-9 getopt-long))
>
> (define spec
>
> '((foo (single-char #\f) (value #t))
>
> (bar (single-char #\b) (value #t))))
>
> (let* ((args (program-arguments))
>
> (opts (getopt-long args spec)))
>
> (simple-format #t "program arguments:\n")
>
> (simple-format #t "~S\n" args)
>
> (simple-format #t "\ngetopt using option-ref:\n")
>
> (simple-format #t "foo: ~S\n" (option-ref opts 'foo #f))
>
> (simple-format #t "bar: ~S\n" (option-ref opts 'bar #f))
>
> (simple-format #t "\ngetopt using option-ref/many:\n")
>
> (simple-format #t "foo: ~S\n" (option-ref/many opts 'foo #f))
>
> (simple-format #t "bar: ~S\n" (option-ref/many opts 'bar #f))
>
> )
>
>
>
> *** getopt-long.scm-orig	2015-10-15 06:40:29.000000000 -0700
> --- getopt-long.scm	2015-10-17 09:42:41.000000000 -0700
> ***************
> *** 154,159 ****
> --- 154,173 ----
>   ;;; (option-ref (getopt-long ...) 'x-includes 42) => "/usr/include"
>   ;;; (option-ref (getopt-long ...) 'not-a-key! 31) => 31
>   
> + ;;; (option-ref/many OPTIONS KEY DEFAULT)
> + ;;; Return value in alist OPTIONS using KEY, a symbol; or DEFAULT if not
> + ;;; found.  If multiple arg-options provided a list is returned.  The value
> + ;;; is either a string, a list or `#t'.
> + ;;;
> + ;;; For example, if the above was executed with multiple x-includes flags,
> + ;;; then all will be returned in a list:
> + ;;;
> + ;;; (getopt-long '("my-prog" "-vk" "/tmp" "foo1" "--x-includes=/usr/include"
> + ;;;                "--x-includes=/opt/includd" "--" "-fred" "foo2" "foo3")
> + ;;;                grammar)
> + ;;; (option-ref/many (getopt-long ...) 'x-includes 42)
> + ;;; => ("/usr/include" "/opt/include")
> + 
>   ;;; Code:
>   
>   (define-module (ice-9 getopt-long)
> ***************
> *** 162,168 ****
>     #:use-module (ice-9 match)
>     #:use-module (ice-9 regex)
>     #:use-module (ice-9 optargs)
> !   #:export (getopt-long option-ref))
>   
>   (define %program-name (make-fluid "guile"))
>   (define (program-name)
> --- 176,182 ----
>     #:use-module (ice-9 match)
>     #:use-module (ice-9 regex)
>     #:use-module (ice-9 optargs)
> !   #:export (getopt-long option-ref option-ref/many))
>   
>   (define %program-name (make-fluid "guile"))
>   (define (program-name)
> ***************
> *** 368,371 ****
> --- 382,397 ----
>   The value is either a string or `#t'."
>     (or (assq-ref options key) default))
>   
> + (define (option-ref/many options key default)
> +   "Return value, or values, in alist OPTIONS using KEY, a symbol; or DEFAULT if not found.
> + The value is either a string, a list or `#t'."
> +   (let loop ((rez #f) (opts options))
> +     (if (null? opts) (or rez default)
> + 	(if (eq? key (caar opts))
> + 	    (cond
> + 	     ((pair? rez) (loop (cons (cdar opts) res) (cdr opts)))
> + 	     (rez (loop (list (cdar opts) rez) (cdr opts)))
> + 	     (else (loop (cdar opts) (cdr opts))))
> + 	    (loop rez (cdr opts))))))
> + 
>   ;;; getopt-long.scm ends here