Recently I needed to be able to recognize multiple use of an option when
using getopt-long. For example, the gcc "-L" option can be specified
multiple times for various paths. The option-ref helper function only
seems to get the most recent use of an option using assq. I couldn't see
any other way in the getopt-long API to do it, so added a helper
function option-ref-list (see patch vs stable-2.0).
>From 66723614a07b73d87cd018d2944e9f6040c8933c Mon Sep 17 00:00:00 2001
From: Andrew Horton <andrew.j.hor...@gmail.com>
Date: Wed, 30 Nov 2011 22:46:26 +0000
Subject: [PATCH] Add a function, option-ref-list, to getopt-long to allow
multiple values to be retrieved for a specified argument.
---
doc/ref/mod-getopt-long.texi | 25 +++++++++++++++++++++++--
module/ice-9/getopt-long.scm | 12 +++++++++++-
2 files changed, 34 insertions(+), 3 deletions(-)
diff --git a/doc/ref/mod-getopt-long.texi b/doc/ref/mod-getopt-long.texi
index 07fab81..745f5a6 100644
--- a/doc/ref/mod-getopt-long.texi
+++ b/doc/ref/mod-getopt-long.texi
@@ -7,8 +7,8 @@
@node getopt-long
@section The (ice-9 getopt-long) Module
-The @code{(ice-9 getopt-long)} module exports two procedures:
-@code{getopt-long} and @code{option-ref}.
+The @code{(ice-9 getopt-long)} module exports three procedures:
+@code{getopt-long}, @code{option-ref}, and @code{option-ref-list}.
@itemize @bullet
@item
@@ -21,6 +21,12 @@ structure that encapsulates the results of the parsing.
@item
@code{option-ref} then takes the parsed data structure and a specific
option's name, and returns information about that option in particular.
+
+@item
+@code{option-ref-list} also takes the parsed data structure and a specific
+option's name, but returns a list of matching options. This is useful if
+you want to allow an option to be specified multiple times with different
+values.
@end itemize
To make these procedures available to your Guile script, include the
@@ -33,6 +39,7 @@ top, before the first usage of @code{getopt-long} or
@code{option-ref}.
* Command Line Format:: The expected command line format.
* getopt-long Reference:: Full documentation for @code{getopt-long}.
* option-ref Reference:: Full documentation for @code{option-ref}.
+* option-ref-list Reference:: Full documentation for
@code{option-ref-list}.
@end menu
@@ -359,3 +366,17 @@ option value from the command line, or the default value.
The special key @code{'()} can be used to get a list of all
non-option arguments.
+
+@node option-ref-list Reference
+@subsection Reference Documentation for @code{option-ref-list}
+
+@deffn {Scheme Procedure} option-ref-list options key default
+Search @var{options} for any command line option named @var{key} and
+return a list of matching values, if found. If none were found, @var{default}
+is returned. This variant of @code{option-ref} is useful if you want the
+user to be able to specify an option/value pair multiple times.
+@var{options} must be the result of a call to @code{getopt-long}.
+@end deffn
+
+@code{option-ref-list} always succeeds, either by returning the requested
+option value from the command line, or the default value.
diff --git a/module/ice-9/getopt-long.scm b/module/ice-9/getopt-long.scm
index 930ac0d..38d5a32 100644
--- a/module/ice-9/getopt-long.scm
+++ b/module/ice-9/getopt-long.scm
@@ -158,11 +158,12 @@
(define-module (ice-9 getopt-long)
#:use-module ((ice-9 common-list) #:select (remove-if-not))
+ #:use-module (srfi srfi-1)
#:use-module (srfi srfi-9)
#:use-module (ice-9 match)
#:use-module (ice-9 regex)
#:use-module (ice-9 optargs)
- #:export (getopt-long option-ref))
+ #:export (getopt-long option-ref option-ref-list))
(define %program-name (make-fluid "guile"))
(define (program-name)
@@ -369,4 +370,13 @@ to add a `single-char' clause to the option description."
The value is either a string or `#t'."
(or (assq-ref options key) default))
+(define (option-ref-list options key default)
+ "Return list of matching values in alist OPTIONS using KEY, a symbol; or
DEFAULT if not found."
+ (let ((vals (fold (lambda (x l)
+ (if (eq? key (car x))
+ (cons (cdr x) l)
+ l))
+ '() options)))
+ (if (null? vals) default vals)))
+
;;; getopt-long.scm ends here
--
1.7.8.rc4
