=== modified file 'lisp/progmodes/perl-mode.el'
--- lisp/progmodes/perl-mode.el	2013-05-07 18:06:13 +0000
+++ lisp/progmodes/perl-mode.el	2013-06-01 13:28:52 +0000
@@ -163,39 +163,7 @@
   :version "24.4"
   :type 'boolean)
 
-(defconst perl--prettify-symbols-alist
-  '(;;("andalso" . ?∧) ("orelse"  . ?∨) ("as" . ?≡)("not" . ?¬)
-    ;;("div" . ?÷) ("*"   . ?×) ("o"   . ?○)
-    ("->"  . ?→)
-    ("=>"  . ?⇒)
-    ;;("<-"  . ?←) ("<>"  . ?≠) (">="  . ?≥) ("<="  . ?≤) ("..." . ?⋯)
-    ("::" . ?∷)
-    ))
-
-(defun perl--font-lock-compose-symbol ()
-  "Compose a sequence of ascii chars into a symbol.
-Regexp match data 0 points to the chars."
-  ;; Check that the chars should really be composed into a symbol.
-  (let* ((start (match-beginning 0))
-	 (end (match-end 0))
-	 (syntaxes (if (eq (char-syntax (char-after start)) ?w)
-		       '(?w) '(?. ?\\))))
-    (if (or (memq (char-syntax (or (char-before start) ?\ )) syntaxes)
-	    (memq (char-syntax (or (char-after end) ?\ )) syntaxes)
-            (nth 8 (syntax-ppss)))
-	;; No composition for you.  Let's actually remove any composition
-	;; we may have added earlier and which is now incorrect.
-	(remove-text-properties start end '(composition))
-      ;; That's a symbol alright, so add the composition.
-      (compose-region start end (cdr (assoc (match-string 0)
-                                            perl--prettify-symbols-alist)))))
-  ;; Return nil because we're not adding any face property.
-  nil)
-
-(defun perl--font-lock-symbols-keywords ()
-  (when perl-prettify-symbols
-    `((,(regexp-opt (mapcar 'car perl--prettify-symbols-alist) t)
-       (0 (perl--font-lock-compose-symbol))))))
+(make-obsolete-variable 'perl-prettify-symbols 'prog-prettify-symbols "24.4")
 
 (defconst perl-font-lock-keywords-1
   '(;; What is this for?
@@ -244,7 +212,7 @@
      ("\\<\\(continue\\|goto\\|last\\|next\\|redo\\)\\>[ \t]*\\(\\sw+\\)?"
       (1 font-lock-keyword-face) (2 font-lock-constant-face nil t))
      ("^[ \t]*\\(\\sw+\\)[ \t]*:[^:]" 1 font-lock-constant-face)
-     ,@(perl--font-lock-symbols-keywords)))
+     ,@(prog--font-lock-symbols-keywords)))
   "Gaudy level highlighting for Perl mode.")
 
 (defvar perl-font-lock-keywords perl-font-lock-keywords-1

=== modified file 'lisp/simple.el'
--- lisp/simple.el	2013-05-25 02:21:49 +0000
+++ lisp/simple.el	2013-06-01 13:23:00 +0000
@@ -400,6 +400,55 @@
   ;; Any programming language is always written left to right.
   (setq bidi-paragraph-direction 'left-to-right))
 
+(defconst prog--prettify-symbols-alist-basic
+  '(("->"  . ?→)
+    ("=>"  . ?⇒)
+    ("::" . ?∷)
+    )
+  "Basic list of symbols to prettify, useful in most languages.")
+
+(defconst prog--prettify-symbols-alist-extended
+  (append prog--prettify-symbols-alist-basic
+          '(("andalso" . ?∧) ("orelse"  . ?∨) ("as" . ?≡)("not" . ?¬)
+            ("div" . ?÷) ("*"   . ?×) ("o"   . ?○)
+            ("<-"  . ?←) ("<>"  . ?≠) (">="  . ?≥) ("<="  . ?≤) ("..." . ?⋯)
+            ))
+  "Extended list of symbols to prettify.")
+
+(defcustom prog-prettify-symbols nil
+  "Which symbols should be prettified.
+Set to an alist in the form `((\"->\" . ?→) ...)'."
+  :type `(choice
+          (const :tag "Basic list: -> => ::" ,prog--prettify-symbols-alist-basic)
+          (const :tag "Extended list: basic plus much more" ,prog--prettify-symbols-alist-extended)
+          (alist :tag "Define your own list" :key-type string :value-type character))
+  :group 'languages)
+
+(defun prog--font-lock-compose-symbol ()
+  "Compose a sequence of ascii chars into a symbol.
+Regexp match data 0 points to the chars."
+  ;; Check that the chars should really be composed into a symbol.
+  (let* ((start (match-beginning 0))
+	 (end (match-end 0))
+	 (syntaxes (if (eq (char-syntax (char-after start)) ?w)
+		       '(?w) '(?. ?\\))))
+    (if (or (memq (char-syntax (or (char-before start) ?\ )) syntaxes)
+	    (memq (char-syntax (or (char-after end) ?\ )) syntaxes)
+            (nth 8 (syntax-ppss)))
+	;; No composition for you.  Let's actually remove any composition
+	;; we may have added earlier and which is now incorrect.
+	(remove-text-properties start end '(composition))
+      ;; That's a symbol alright, so add the composition.
+      (compose-region start end (cdr (assoc (match-string 0)
+                                            prog--prettify-symbols-alist)))))
+  ;; Return nil because we're not adding any face property.
+  nil)
+
+(defun prog--font-lock-symbols-keywords ()
+  (when prog-prettify-symbols
+    `((,(regexp-opt (mapcar 'car prog-prettify-symbols) t)
+       (0 (prog--font-lock-compose-symbol))))))
+
 ;; Making and deleting lines.
 
 (defvar hard-newline (propertize "\n" 'hard t 'rear-nonsticky '(hard))