diff --git a/el/sclang-help.el b/el/sclang-help.el
index 97d998f..6d5b2e5 100644
--- a/el/sclang-help.el
+++ b/el/sclang-help.el
@@ -16,10 +16,10 @@
 ;; USA
 
 (eval-when-compile
-  (require 'cl)
   (require 'font-lock))
 
 ;; (require 'w3m) ;; not needed during compilation
+(require 'cl-lib)
 (require 'sclang-util)
 (require 'sclang-interp)
 (require 'sclang-language)
@@ -36,7 +36,7 @@
 
 (defcustom sclang-help-path (list sclang-system-help-dir
 				  "~/.local/share/SuperCollider/Help")
-  "*List of directories where SuperCollider help files are kept."
+  "List of directories where SuperCollider help files are kept."
   :group 'sclang-interface
   :version "21.4"
   :type '(repeat directory))
@@ -46,7 +46,7 @@
   "List of SuperCollider extension directories.")
 
 (defcustom sclang-help-fill-column fill-column
-  "*Column beyond which automatic line-wrapping in RTF help files should happen."
+  "Column beyond which automatic line-wrapping in RTF help files should happen."
   :group 'sclang-interface
   :version "21.3"
   :type 'integer)
@@ -177,10 +177,10 @@
 			      (Helvetica-Bold . variable-pitch)
 			      (Monaco . nil)))
 
-(defstruct sclang-rtf-state
+(cl-defstruct sclang-rtf-state
   output font-table font face pos)
 
-(macrolet ((rtf-p (pos) `(plist-get (text-properties-at ,pos) 'rtf-p)))
+(cl-macrolet ((rtf-p (pos) `(plist-get (text-properties-at ,pos) 'rtf-p)))
   (defun sclang-rtf-p (pos) (rtf-p pos))
   (defun sclang-code-p (pos) (not (rtf-p pos))))
 
@@ -416,16 +416,15 @@
 (defun sclang-skip-help-directory-p (path)
   "Answer t if PATH should be skipped during help file indexing."
   (let ((directory (file-name-nondirectory path)))
-    (reduce (lambda (a b) (or a b))
-	    (mapcar (lambda (regexp) (string-match regexp directory))
-		    '("^\.$" "^\.\.$" "^CVS$" "^\.svn$" "^_darcs$")))))
+    (cl-some (lambda (regexp) (string-match regexp directory))
+	     '("^\.$" "^\.\.$" "^CVS$" "^\.svn$" "^_darcs$"))))
 
 (defun sclang-filter-help-directories (list)
   "Remove paths to be skipped from LIST of directories."
-  (remove-if (lambda (x)
-	       (or (not (file-directory-p x))
-		   (sclang-skip-help-directory-p x)))
-	     list))
+  (cl-remove-if (lambda (x)
+		  (or (not (file-directory-p x))
+		      (sclang-skip-help-directory-p x)))
+		list))
 
 (defun sclang-directory-files-save (directory &optional full match nosort)
   "Return a list of names of files in DIRECTORY, or nil on error."
@@ -464,8 +463,8 @@
   "Build a help topic alist from directories in DIRS, with initial RESULT."
   (if dirs
       (let* ((files (sclang-directory-files-save (car dirs) t))
-	     (topics (remove-if 'null (mapcar 'sclang-help-topic-name files)))
-	     (new-dirs	(sclang-filter-help-directories files)))
+	     (topics (remq nil (mapcar 'sclang-help-topic-name files)))
+	     (new-dirs (sclang-filter-help-directories files)))
 	(sclang-make-help-topic-alist
 	 (append new-dirs (cdr dirs))
 	 (append topics result)))
diff --git a/el/sclang-language.el b/el/sclang-language.el
index 4303a83..79bc9b1 100644
--- a/el/sclang-language.el
+++ b/el/sclang-language.el
@@ -15,9 +15,7 @@
 ;; Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301
 ;; USA
 
-(eval-when-compile
-  (require 'cl))
-
+(require 'cl-lib)
 (require 'sclang-browser)
 (require 'sclang-interp)
 (require 'sclang-util)
@@ -219,8 +217,8 @@ low-resource systems."
  'symbolTable
  (lambda (arg)
    (when (and sclang-use-symbol-table arg)
-     (setq sclang-symbol-table (sort arg 'string<))
-     (setq sclang-class-list (remove-if
+     (setq sclang-symbol-table (sort arg 'string-lessp))
+     (setq sclang-class-list (cl-remove-if
                               (lambda (x) (or (not (sclang-class-name-p x))
                                               (sclang-string-match "^Meta_" x)))
                               sclang-symbol-table))
@@ -753,46 +751,46 @@ current-directory, iff `sclang-source-directoy' is nil."
 Looks for all repetitive patterns in ITEMS recursively.  Therefore, it is
 computationally expensive, especially when ITEMS is a long list.  If you don't
 want smart pattern guessing, use `sclang-format' directly to format your Pseq."
-  (cl-flet ((find-reps (items)
-	   (let (r)
-	     (while items
-	       (let ((ret (car items))
-		     (skip 1)
-		     (rep (length items)))
-		 (catch 'match-found
-		   (while (>= rep 2)
-		     (let ((i (/ (length items) rep)))
-		       (while (> i 0)
-			 (let ((sublst (subseq items 0 i)))
-			   (when (catch 'equal
-				   (let ((a items))
-				     (loop repeat rep do
-					   (let ((b sublst))
-					     (while b
-					       (unless (eql (car b) (car a))
-						 (throw 'equal nil))
-					       (setq a (cdr a)
-						     b (cdr b)))))
-				     t))
-			     (setq ret (cons rep (if (> i 5)
-						     (find-reps sublst)
-						   sublst))
-				   skip (* i rep))
-			     (throw 'match-found t))
-			   (decf i))))
-		     (decf rep)))
-		 (accept-process-output nil 0 100)
-		 (message "Processed...%S" ret) ;; invent better progress info
-		 (setq r (append r (list ret))
-		       items (nthcdr skip items))))
-	     r))
-	 (elem-to-string (elem)
-	   (cond
-	    ((consp elem)
-	     (concat "Pseq([ "
-		     (mapconcat #'elem-to-string (cdr elem) ", ")
-		     (format " ], %d)" (car elem))))
-	    (t (sclang-object-to-string elem)))))
+  (cl-labels ((find-reps (items)
+	       (let (r)
+		 (while items
+		   (let ((ret (car items))
+			 (skip 1)
+			 (rep (length items)))
+		     (catch 'match-found
+		       (while (>= rep 2)
+			 (let ((i (/ (length items) rep)))
+			   (while (> i 0)
+			     (let ((sublst (cl-subseq items 0 i)))
+			       (when (catch 'equal
+				       (let ((a items))
+					 (cl-loop repeat rep do
+						  (let ((b sublst))
+						    (while b
+						      (unless (eql (car b) (car a))
+							(throw 'equal nil))
+						      (setq a (cdr a)
+							    b (cdr b)))))
+					 t))
+				 (setq ret (cons rep (if (> i 5)
+							 (find-reps sublst)
+						       sublst))
+				       skip (* i rep))
+				 (throw 'match-found t))
+			       (cl-decf i))))
+			 (cl-decf rep)))
+		     (accept-process-output nil 0 100)
+		     (message "Processed...%S" ret) ;; invent better progress info
+		     (setq r (append r (list ret))
+			   items (nthcdr skip items))))
+		 r))
+	      (elem-to-string (elem)
+	       (cond
+		((consp elem)
+		 (concat "Pseq([ "
+			 (mapconcat #'elem-to-string (cdr elem) ", ")
+			 (format " ], %d)" (car elem))))
+		(t (sclang-object-to-string elem)))))
     (let ((compressed (find-reps items)))
       (if (and (= (length compressed) 1) (consp (car compressed)))
 	  (elem-to-string (car compressed))
diff --git a/el/sclang-mode.el b/el/sclang-mode.el
index e90396c..377ef32 100644
--- a/el/sclang-mode.el
+++ b/el/sclang-mode.el
@@ -15,9 +15,9 @@
 ;; Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301
 ;; USA
 
+(require 'cl-lib)
+
 (eval-when-compile
-  (require 'cl)
-  (load "cl-seq" nil t)
   (require 'font-lock)
   (require 'sclang-util))
 
@@ -255,7 +255,7 @@
         (let ((thing (thing-at-point 'word)))
           (if (null thing)
               (setq res nil continue nil)
-            (when (position (substring-no-properties thing) sclang-class-list :test 'equal)
+            (when (cl-position (substring-no-properties thing) sclang-class-list :test 'equal)
               (setq continue nil))))))
     res))
 
@@ -450,10 +450,7 @@ Returns the column to indent to."
     (sclang-document-edited-p . (prSetEdited (buffer-modified-p)))))
 
 (defmacro sclang-next-document-id ()
-  `(incf sclang-document-counter))
-
-(defun sclang-document-list ()
-  sclang-document-list)
+  `(cl-incf sclang-document-counter))
 
 (defun sclang-document-id (buffer)
   (cdr (assq 'sclang-document-id (buffer-local-variables buffer))))
@@ -467,15 +464,15 @@ Returns the column to indent to."
        ,@body)))
 
 (defun sclang-get-document (id)
-  (find-if (lambda (doc) (eq id (sclang-document-id doc)))
-	   (sclang-document-list)))
+  (cl-find-if (lambda (buffer) (eq id (sclang-document-id buffer)))
+	      sclang-document-list))
 
 (defun sclang-init-document ()
   (set (make-local-variable 'sclang-document-id) (sclang-next-document-id))
   (set (make-local-variable 'sclang-document-envir) nil)
   (dolist (assoc sclang-document-property-map)
     (set (make-local-variable (car assoc)) nil))
-  (pushnew (current-buffer) sclang-document-list))
+  (cl-pushnew (current-buffer) sclang-document-list))
 
 (defun sclang-document-update-property-1 (assoc &optional force)
   (when (consp assoc)
@@ -514,7 +511,7 @@ Returns the column to indent to."
     t))
 
 (defun sclang-document-library-startup-hook-function ()
-  (dolist (buffer (sclang-document-list))
+  (dolist (buffer sclang-document-list)
     (with-current-buffer buffer
       (sclang-make-document)))
   (sclang-set-current-document (current-buffer) t))
diff --git a/el/sclang-server.el b/el/sclang-server.el
index 90c9917..1f948db 100644
--- a/el/sclang-server.el
+++ b/el/sclang-server.el
@@ -15,15 +15,16 @@
 ;; Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301
 ;; USA
 
+(require 'cl-lib)
+
 (eval-when-compile
-  (require 'cl)
   (require 'sclang-util)
   (require 'sclang-interp)
   (require 'sclang-language)
   (require 'sclang-mode))
 
 (defcustom sclang-server-panel "Server.default.makeWindow"
-  "*Expression to execute when `sclang-show-server-panel' is invoked."
+  "Expression to execute when `sclang-show-server-panel' is invoked."
   :group 'sclang-interface
   :type '(choice (const "Server.default.makeWindow")
 		 (const "\\SCUM.asClass.do { \\SCUM.asClass.desktop.showServerPanel }")
@@ -61,7 +62,7 @@
  '_updateServer
  (lambda (arg)
    (setq sclang-server-alist
-	 (sort (cdr arg) (lambda (a b) (string< (car a) (car b)))))
+	 (sort (cdr arg) (lambda (a b) (string-lessp (car a) (car b)))))
    (setq sclang-default-server (car arg))
    (unless sclang-current-server-initialized
      ;; only set the current server automatically once after startup
@@ -73,9 +74,9 @@
   "Select next server for display."
   (interactive)
   (sclang-set-server)
-  (let ((list (or (cdr (member-if (lambda (assoc)
-				    (eq (car assoc) sclang-current-server))
-				  sclang-server-alist))
+  (let ((list (or (cdr (cl-member-if (lambda (assoc)
+				       (eq (car assoc) sclang-current-server))
+				     sclang-server-alist))
 		  sclang-server-alist)))
     (setq sclang-current-server (car (car list))))
   (sclang-update-server-info))
@@ -99,8 +100,7 @@
      ["Quit" sclang-server-quit]
      "-"
      ["Free All" sclang-server-free-all :active (sclang-server-running-p)]
-     ["Make Default" sclang-server-make-default]
-     )))
+     ["Make Default" sclang-server-make-default])))
 
 (defun sclang-server-fill-mouse-map (map prefix)
   (define-key map (vector prefix 'mouse-1) 'sclang-mouse-next-server)
diff --git a/el/sclang.el b/el/sclang.el
index 8659f9d..3550287 100644
--- a/el/sclang.el
+++ b/el/sclang.el
@@ -46,9 +46,6 @@
   (interactive)
   (customize-group 'sclang))
 
-(eval-and-compile
-  (require 'cl))
-
 (eval-and-compile
   (let ((load-path
 	 (if (and (boundp 'byte-compile-dest-file)