Minor localization support

docs/01-usage.markdown

@@ -978,6 +978,13 @@ default `man` is usually smart enough to look next to every directory in your
 appropriate subdirectories and it should all Just Work™.  Consult the `man`
 documentation for more information.
 
+Localization notes
+------------------
+
+In general, manual can be written in any language and all text should be given in target language.
+To customize adopt output itself several one can pass localized strings to `make-inteface` in `:usage-string`, `:options-string` and `:examples-string`.
+Given strings are used instead of default ones.
+
 Implementation Specifics
 ------------------------
 

src/main.lisp

@@ -378,7 +378,10 @@
   long-options
   usage
   help
-  manual)
+  manual
+  usage-string
+  options-string
+  examples-string)
 
 (defmethod print-object ((i interface) stream)
   (print-unreadable-object (i stream :type t)
@@ -387,7 +390,7 @@
             (length (options i))
             (length (groups i)))))
 
-(defun make-interface (&key name summary usage help manual examples contents)
+(defun make-interface (&key name summary usage help manual examples contents usage-string options-string examples-string)
   "Create and return a command line interface.
 
   This function takes a number of arguments that define how the interface is
@@ -400,6 +403,10 @@
   * `manual` (optional): a string to use in place of `help` when rendering a man page.
   * `examples` (optional): an alist of `(prose . command)` conses to render as a list of examples.
   * `contents` (optional): a list of options and groups.  Ungrouped options will be collected into a single top-level group.
+  * `usage-string` (optional): a string to use as a 'USAGE' line (may be used for localization)
+  * `options-string` (optional): a string to use as a 'Options' line (may be used for localization)
+  * `examples-string` (optional): a string to use as a 'Examples' line (may be used for localization)
+
 
   See the full documentation for more information.
 
@@ -410,14 +417,20 @@
                help string
                manual (or null string)
                examples list
-               contents list)
+               contents list
+               usage-string (or null string)
+               options-string (or null string)
+               examples-string (or null string))
   (let* ((ungrouped-options (remove-if-not #'optionp contents))
          (groups (cons (make-default-group ungrouped-options)
                        (remove-if-not #'groupp contents)))
          (options (loop :for g :in groups :append (options g)))
          (interface (make-instance 'interface
                       :name name
                       :usage usage
+                      :usage-string (or usage-string "USAGE")
+                      :options-string (or options-string "Options")
+                      :examples-string (or examples-string "Examples")
                       :summary summary
                       :help help
                       :manual manual
@@ -709,12 +722,12 @@
     "WIDTH (~D) must be at least 4 greater than OPTION-WIDTH (~D)"
     width option-width)
   (format stream "~A - ~A~2%" (name interface) (summary interface))
-  (format stream "USAGE: ~A ~A~2%" program-name (usage interface))
+  (format stream "~A: ~A ~A~2%" (usage-string interface) program-name (usage interface))
   (format stream (bobbin:wrap (help interface) width))
   (format stream "~%")
   (dolist (group (groups interface))
     (when (or (options group) (help group))
-      (format stream "~%~A:~%" (or (title group) (name group) "Options"))
+      (format stream "~%~A:~%" (or (title group) (name group) (options-string interface)))
       (let* ((help (help group))
              (help-column 2)
              (help-width (- width help-column))
@@ -731,7 +744,7 @@
          (example-column 2)
          (example-width (- width example-column)))
     (when (and examples include-examples)
-      (format stream "~%Examples:~%")
+      (format stream "~%~A:~%" (examples-string interface))
       (loop :for (prose . command) :in examples :do
             (format stream "~%~{  ~A~^~%~}~2%      ~A~%"
                     (bobbin:wrap (list prose) example-width)
@@ -764,11 +777,13 @@
               :include-examples include-examples)
   (funcall exit-function exit-code))
 
+(defparameter *error-string* "error")
+
 (defun print-error-and-exit (error &key
                              (stream *error-output*)
                              (exit-function #'exit)
                              (exit-code 1)
-                             (prefix "error: "))
+                             (prefix (format nil "~A: " *error-string*)))
   "Print `prefix` and `error` to `stream` and exit.
 
   Example:

src/package.lisp

@@ -31,5 +31,7 @@
     :first
     :last
 
+    :*error-string*
+
     )
   (:shadow :collect :reduce :first :last))