Add Licensing and Contributing

[opera] / src / main / opera.lisp

diff --git a/src/main/opera.lisp b/src/main/opera.lisp
index b66a4c07cf1fecdafaab2eb3a7dfbd04e585317b..3e45a9e4a76b1317a453c1b288ea561a7aeeab7e 100644 (file)
--- a/src/main/opera.lisp
+++ b/src/main/opera.lisp
@@ -1,3 +1,4 @@
+; Copyright 2022 Frank Duncan (frank@consxy.com) under AGPL3.  See distributed LICENSE.txt.
 (defpackage #:opera
  (:use :common-lisp)
  (:export #:process-arguments #:usage
@@ -187,8 +188,11 @@
 (defun option-present (option-name parsed-options)
  (find option-name parsed-options :key #'car))
 
-(defun option-argument (option-name parsed-options)
- (cadr (assoc option-name parsed-options)))
+(defun option-argument (option-name parsed-options &optional default)
+ (if
+  (option-present option-name parsed-options)
+  (cadr (assoc option-name parsed-options))
+  default))
 
 (defun option-arguments (option-name parsed-options)
  (mapcar #'cadr (remove option-name parsed-options :key #'car :test-not #'eql)))