From 139862d66ddff37663038c8abe31b4ce7a87599d Mon Sep 17 00:00:00 2001
From: Daniel Borchmann <daniel@algebra20.de>
Date: Sat, 11 Nov 2017 09:06:41 +0100
Subject: [PATCH] =?UTF-8?q?[Misc]=20Introduce=20variable=20=E2=80=98on-win?=
 =?UTF-8?q?dows=E2=80=99?=
MIME-Version: 1.0
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Content-Transfer-Encoding: 8bit

to increase readability
---
 init.el               | 13 ++++++++-----
 site-lisp/db-emms.el  |  2 +-
 site-lisp/db-utils.el |  6 +++---
 3 files changed, 12 insertions(+), 9 deletions(-)

diff --git a/init.el b/init.el
index 91cd99b..6f89d28 100644
--- a/init.el
+++ b/init.el
@@ -262,7 +262,7 @@ _h_   _l_   _o_k        _y_ank
 
   ;; Environment Variables
 
-  (unless (memq system-type '(windows-nt cygwin))
+  (unless on-windows
     (ignore-errors
       (exec-path-from-shell-copy-envs '("SSH_AUTH_SOCK"
                                         "SSH_AGENT_PID"
@@ -281,7 +281,7 @@ _h_   _l_   _o_k        _y_ank
 
   ;; Start Server when on Windows
 
-  (when (memq system-type '(windows-nt cygwin))
+  (when on-windows
     (server-start))
 
   t)
@@ -307,6 +307,9 @@ _h_   _l_   _o_k        _y_ank
   :group 'help
   :tag "Personal settings")
 
+(defconst on-windows (memq system-type '(windows-nt cygwin))
+  "Non-nil if and only if this instance of Emacs runs on Windows.")
+
 
 ;; * Builtin Variables
 
@@ -360,7 +363,7 @@ _h_   _l_   _o_k        _y_ank
       x-underline-at-descent-line t
       search-whitespace-regexp "[ \t\r\n]+")
 
-(when (memq system-type '(windows-nt cygwin))
+(when on-windows
   ;; treat memory for display time ...  but hey, this is Windows, memory doesn’t
   ;; matter!
   (setq inhibit-compacting-font-caches t))
@@ -714,7 +717,7 @@ Certificates are assumed to be of the form *.crt."
             (dolist (extension '(".out" ".synctex.gz" ".thm"))
               (add-to-list 'dired-latex-unclean-extensions extension))
 
-            (if (memq system-type '(windows-nt cygwin))
+            (if on-windows
                 (setq dired-guess-shell-alist-user
                       '(("\\.pdf\\'" "cmd /c")
                         ("\\.docx\\'" "cmd /c")
@@ -766,7 +769,7 @@ Certificates are assumed to be of the form *.crt."
                   (error "No more than 2 files should be marked"))))
 
             (require 'dired-quick-sort)
-            (when (eq system-type 'windows-nt)
+            (when on-windows
               (setq ls-lisp-use-insert-directory-program t))
             (dired-quick-sort-setup)
 
diff --git a/site-lisp/db-emms.el b/site-lisp/db-emms.el
index b8a5748..5fa27d9 100644
--- a/site-lisp/db-emms.el
+++ b/site-lisp/db-emms.el
@@ -105,7 +105,7 @@ that we also follow symbolic links."
                                             (point-max))
                           "\n"))))
 
-(unless (memq system-type '(windows-nt ms-dos))
+(unless on-windows
   (setq emms-source-file-directory-tree-function
         #'db/emms-source-file-directory-tree-find))
 
diff --git a/site-lisp/db-utils.el b/site-lisp/db-utils.el
index 69edf50..ef3515e 100644
--- a/site-lisp/db-utils.el
+++ b/site-lisp/db-utils.el
@@ -329,9 +329,9 @@ path."
 
 (defun db/system-open (path)
   "Open PATH with default program as defined by the underlying system."
-  (ecase system-type
-    ((windows-nt cygwin) (w32-shell-execute "open" path))
-    ((gnu/linux) (start-process "" nil "xdg-open" path))))
+  (if on-windows
+      (w32-shell-execute "open" path)
+    (start-process "" nil "xdg-open" path)))
 
 (defvar db/helm-source-important-documents
   '((name . "Important files")