[STUMP] [PATCH] Use multiple directories when searching for modules

[Diogo F. S. Ramos]

Having only one directory as the source of modules limits where the
user can collect these modules, specially if StumpWM is a system-wide
installation.

This patch adds a new variable, `*contrib-dirs*', which holds a list
of directories where StumpWM should search for modules.

To preserve backward compatibility, `*contrib-dir*' still exists and
behaves as expected.

When the user decides to use this new feature, both variables are
taken into account, with `*contrib-dirs*' taking precedence over the
old variable; if no module is found inside `*contrib-dirs*',
`*contrib-dir*' is used.  The reasoning for this is that
`*contrib-dir*' has a default value to look for contrib modules
distributed with StumpWM, so an user might want to add new modules,
possibly patched versions of the ones distributed with StumpWM.

Two functions, `set-contrib-dirs' and `add-contrib-dir' are exported
to maintain the same semantics of `set-contrib-dir', but there is no
command for them.
---
 module.lisp | 44 +++++++++++++++++++++++++++++++++++++-------
 1 file changed, 37 insertions(+), 7 deletions(-)

diff --git a/module.lisp b/module.lisp
index 7f65a05..90262be 100644
--- a/module.lisp
+++ b/module.lisp
@@ -28,7 +28,11 @@
           list-modules
          *contrib-dir*
          set-contrib-dir
-          find-module))
+          find-module
+          *contrib-dirs*
+          set-contrib-dirs
+          add-contrib-dir
+          ))
 
 (defun module-string-as-directory (dir)
   (unless (string= "/" (subseq dir (1- (length dir))))
@@ -41,10 +45,28 @@
                                                   '(:relative "contrib")))
   "The location of the contrib modules on your system.")
 
+(defvar *contrib-dirs*
+  nil
+  "Additional list of directories where to find StumpWM modules.")
+
 (defcommand set-contrib-dir (dir) ((:string "Directory: "))
     "Sets the location of the contrib modules"
   (setf *contrib-dir* (module-string-as-directory dir)))
 
+(defun set-contrib-dirs (list-of-directories)
+  "Set the multiple locations of StumpWM modules."
+  (setf *contrib-dirs* (mapcar 'module-string-as-directory 
list-of-directories)))
+
+(defun add-contrib-dir (directory)
+  "Add a new location where StumpWM can find modules."
+  (push (module-string-as-directory directory) *contrib-dirs*))
+
+(defun merge-contribs ()
+  "Merge *contrib-dir* and *contrib-dirs*.
+
+This function dictates the policy taken for directory precedence."
+  (append *contrib-dirs* (list *contrib-dir*)))
+
 (define-stumpwm-type :module (input prompt)
   (or (argument-pop-rest input)
       (completing-read (current-screen) prompt (list-modules) :require-match 
t)))
@@ -52,14 +74,22 @@
 (defun list-modules ()
   "Return a list of the available modules."
   (mapcar 'pathname-name
-          (directory (make-pathname :defaults *contrib-dir*
-                                   :name :wild
-                                   :type "lisp"))))
+          (loop
+             for dir in (merge-contribs)
+             append (directory (make-pathname :defaults dir
+                                              :name :wild
+                                              :type "lisp")))))
 
 (defun find-module (name)
-  (probe-file (make-pathname :defaults *contrib-dir*
-                             :name name
-                             :type "lisp")))
+  "Search for a module inside contrib sources.
+
+This will return the first match."
+  (some #'probe-file
+        (mapcar (lambda (dir)
+                  (make-pathname :defaults dir
+                                 :name name
+                                 :type "lisp"))
+                (merge-contribs))))
 
 (defcommand load-module (name) ((:module "Load Module: "))
   "Loads the contributed module with the given NAME."
-- 
1.8.4.rc3