mule-conf.el (prefer-utf-8): New coding system.

(file-coding-system-alist): Use prefer-utf-8 as default for Elisp
files.

1 files changed, 13 insertions, 1 deletions

diff --git a/lisp/international/mule-conf.el b/lisp/international/mule-conf.el
index 48487b850df..a84054b498b 100644
--- a/lisp/international/mule-conf.el
+++ b/lisp/international/mule-conf.el
@@ -1225,6 +1225,18 @@
 (define-coding-system-alias 'dos 'undecided-dos)
 (define-coding-system-alias 'mac 'undecided-mac)
 
+(define-coding-system 'prefer-utf-8
+  "Like `undecided' but prefer UTF-8 when appropriate.
+On decoding, if the source contains 8-bit codes and they all
+are valid UTF-8 sequences, detect the source as UTF-8 encoding
+regardless of the coding priority.
+On encoding, if the source contains non-ASCII characters, encode them
+by UTF-8."
+  :coding-type 'undecided
+  :mnemonic ?-
+  :charset-list '(emacs)
+  :prefer-utf-8 t)
+
 (define-coding-system 'raw-text
   "Raw text, which means text contains random 8-bit codes.
 Encoding text with this coding system produces the actual byte
@@ -1508,7 +1520,7 @@ for decoding and encoding files, process I/O, etc."
 (setq file-coding-system-alist
       (mapcar (lambda (arg) (cons (purecopy (car arg)) (cdr arg)))
       '(("\\.elc\\'" . utf-8-emacs)
-        ("\\.el\\'" . utf-8)
+        ("\\.el\\'" . prefer-utf-8)
         ("\\.utf\\(-8\\)?\\'" . utf-8)
         ("\\.xml\\'" . xml-find-file-coding-system)
         ;; We use raw-text for reading loaddefs.el so that if it