(install-prefix, install-elisp-prefix, install-detect-elisp-directory):

Rewrite.

diff --git a/install.el b/install.el
index 9db27cf..c961fe3 100644 (file)
--- a/install.el
+++ b/install.el
@@ -125,20 +125,29 @@ See `install-elisp-modules' for more information."
 ;;; @ detect install path
 ;;;
 
-;; install to shared directory (maybe "/usr/local")
 (defvar install-prefix
-  (if (or (<= emacs-major-version 18)
-         (featurep 'xemacs)
-         (and (boundp 'system-configuration-options) ; 19.29 or later
-              (string= system-configuration-options "NT"))) ; for Meadow
-      (expand-file-name "../../.." exec-directory)
+  (cond
+   ((<= emacs-major-version 18)
+    ;; The default of `exec-directory' is "/usr/local/emacs/etc".
+    ;; (See src/paths.h-dist)
+    (expand-file-name "../.." exec-directory))
+   ((featurep 'meadow)
+    ;; I have no idea, sorry.
+    (expand-file-name "../../.." data-directory))
+   ((featurep 'xemacs)
+    ;; The default of 'data-directory' is
+    ;; "/usr/local/lib/xemacs-$VERSION/etc".
+    (expand-file-name "../../.." data-directory))
+   (t
+    ;; The default of 'data-directory' is
+    ;; "/usr/local/lib/emacs/$VERSION/etc" (19.28 and earlier), or
+    ;; "/usr/local/share/emacs/$VERSION/etc" (19.29 and later).
     (expand-file-name "../../../.." data-directory)))
+  "Install prefix, normally \"/usr/local\".")
 
-(defvar install-elisp-prefix
-  (if (>= emacs-major-version 19)
-      "site-lisp"
-    ;; v18 does not have standard site directory.
-    "local.lisp"))
+;; v18 does not have the default, please set explicitly.
+(defvar install-elisp-prefix "site-lisp"
+  "Prefix for local lisp directory, normally \"site-lisp\".")
 
 (defun install-detect-elisp-directory (&optional prefix elisp-prefix
                                                 allow-version-specific)
@@ -146,21 +155,24 @@ See `install-elisp-modules' for more information."
       (setq prefix install-prefix))
   (or elisp-prefix
       (setq elisp-prefix install-elisp-prefix))
-  (or (catch 'tag
-       (let ((rest default-load-path)
-             (regexp (concat "^"
-                             (expand-file-name (concat ".*/" elisp-prefix)
-                                               prefix)
-                             "/?$")))
-         (while rest
-           (if (string-match regexp (car rest))
-               (if (or allow-version-specific
-                       (not (string-match (format "/%d\\.%d"
-                                                  emacs-major-version
-                                                  emacs-minor-version)
-                                          (car rest))))
-                   (throw 'tag (car rest))))
-           (setq rest (cdr rest)))))
+  (or (let ((rest default-load-path)
+           (regexp (concat "^"
+                           (expand-file-name (concat ".*/" elisp-prefix)
+                                             prefix)
+                           "/?$"))
+           (found nil))
+       (while (and rest (not found))
+         (if (string-match regexp (car rest))
+             (if (or allow-version-specific
+                     (not (string-match (format "/%d\\.%d"
+                                                emacs-major-version
+                                                emacs-minor-version)
+                                        (car rest))))
+                 (setq found (car rest))))
+         (setq rest (cdr rest)))
+       found)
+      ;; we couldn't find appropriate directory from `load-path'.
+      ;; use the default directory for each emacsen.
       (expand-file-name (concat (if (and (not (featurep 'xemacs))
                                         (or (>= emacs-major-version 20)
                                             (and (= emacs-major-version 19)
@@ -168,10 +180,7 @@ See `install-elisp-modules' for more information."
                                    "share/"
                                  "lib/")
                                (cond
-                                ((featurep 'xemacs)
-                                 (if (featurep 'mule)
-                                     "xmule/"
-                                   "xemacs/"))
+                                ((featurep 'xemacs) "xemacs/")
                                 ;; unfortunately, unofficial mule based on
                                 ;; 19.29 and later use "emacs/" by default.
                                 ((boundp 'MULE) "mule/")