Move gensym to core Elisp

* doc/lispref/symbols.texi (Creating Symbols): Mention gensym right
after make-symbol.
* etc/NEWS: Mention.
* lisp/emacs-lisp/cl-macs.el (cl--gensym-counter): Alias to
gensym-counter.
(cl-gensym): Alias to gensym.
* lisp/emacs-lisp/cl.el: Remove gensym from list of aliases.
* lisp/emacs-lisp/edebug.el (edebug-make-enter-wrapper):
* lisp/emacs-lisp/ert-x.el (ert-with-message-capture):
(ert--expand-should-1, ert--expand-should):
(ert--should-error-handle-error):
* lisp/emacs-lisp/generator.el (cps--gensym):
* lisp/emacs-lisp/gv.el (setf):
* lisp/emacs-lisp/inline.el (inline--do-letlisteval):
* lisp/emacs-lisp/pcase.el (pcase--make-docstring, pcase-dolist):
(pcase--funcall, pcase--u1): Use gensym.
* lisp/subr.el (gensym-counter): New variable.
(gensym): New function, assimilated from cl-lib.

12 files changed, 45 insertions, 32 deletions

diff --git a/doc/lispref/symbols.texi b/doc/lispref/symbols.texi
index e6ea8a1cc09..2d9ec6fda30 100644
--- a/doc/lispref/symbols.texi
+++ b/doc/lispref/symbols.texi
@@ -273,6 +273,13 @@ distinct uninterned symbol whose name is also @samp{foo}.
 @end example
 @end defun
 
+@defun gensym &optional prefix
+This function returns a symbol using @code{make-symbol}, whose name is
+made by appending @code{gensym-counter} to @var{prefix}.  The prefix
+defaults to @code{"G"}.  If @var{prefix} is a number, it replaces the
+value of the counter.
+@end defun
+
 @defun intern name &optional obarray
 This function returns the interned symbol whose name is @var{name}.  If
 there is no such symbol in the obarray @var{obarray}, @code{intern}
diff --git a/etc/NEWS b/etc/NEWS
index 3f1df23ec30..af29b29264d 100644
--- a/etc/NEWS
+++ b/etc/NEWS
@@ -1525,6 +1525,9 @@ It avoids unnecessary consing (and garbage collection).
 +++
 ** 'car' and 'cdr' compositions 'cXXXr' and 'cXXXXr' are now part of Elisp.
 
++++
+** 'gensym' is now part of Elisp.
+
 ---
 ** 'if-let*', 'when-let*', and 'and-let*' are new in subr-x.el.
 The incumbent 'if-let' and 'when-let' are now aliases.
diff --git a/lisp/emacs-lisp/cl-macs.el b/lisp/emacs-lisp/cl-macs.el
index 3405c92e8d4..eee5953882d 100644
--- a/lisp/emacs-lisp/cl-macs.el
+++ b/lisp/emacs-lisp/cl-macs.el
@@ -161,16 +161,9 @@ whether X is known at compile time, macroexpand it completely in
 
 ;;; Symbols.
 
-(defvar cl--gensym-counter 0)
+(defvaralias 'cl--gensym-counter 'gensym-counter)
 ;;;###autoload
-(defun cl-gensym (&optional prefix)
-  "Generate a new uninterned symbol.
-The name is made by appending a number to PREFIX, default \"G\"."
-  (let ((pfix (if (stringp prefix) prefix "G"))
-	(num (if (integerp prefix) prefix
-	       (prog1 cl--gensym-counter
-		 (setq cl--gensym-counter (1+ cl--gensym-counter))))))
-    (make-symbol (format "%s%d" pfix num))))
+(cl--defalias 'cl-gensym 'gensym)
 
 (defvar cl--gentemp-counter 0)
 ;;;###autoload
diff --git a/lisp/emacs-lisp/cl.el b/lisp/emacs-lisp/cl.el
index 73eb9a4e866..306237ca38f 100644
--- a/lisp/emacs-lisp/cl.el
+++ b/lisp/emacs-lisp/cl.el
@@ -250,7 +250,6 @@
                eval-when
                destructuring-bind
                gentemp
-               gensym
                pairlis
                acons
                subst
diff --git a/lisp/emacs-lisp/edebug.el b/lisp/emacs-lisp/edebug.el
index c6ef8d7a99c..3190346497d 100644
--- a/lisp/emacs-lisp/edebug.el
+++ b/lisp/emacs-lisp/edebug.el
@@ -1193,7 +1193,7 @@ circular objects.  Let `read' read everything else."
   ;; Uses the dynamically bound vars edebug-def-name and edebug-def-args.
   ;; Do this after parsing since that may find a name.
   (setq edebug-def-name
-	(or edebug-def-name edebug-old-def-name (cl-gensym "edebug-anon")))
+	(or edebug-def-name edebug-old-def-name (gensym "edebug-anon")))
   `(edebug-enter
     (quote ,edebug-def-name)
     ,(if edebug-inside-func
diff --git a/lisp/emacs-lisp/ert-x.el b/lisp/emacs-lisp/ert-x.el
index 4cf9d9609e9..1413b9cd0bf 100644
--- a/lisp/emacs-lisp/ert-x.el
+++ b/lisp/emacs-lisp/ert-x.el
@@ -295,7 +295,7 @@ This is useful for separating the issuance of messages by the
 code under test from the behavior of the *Messages* buffer."
   (declare (debug (symbolp body))
            (indent 1))
-  (let ((g-advice (cl-gensym)))
+  (let ((g-advice (gensym)))
     `(let* ((,var "")
             (,g-advice (lambda (func &rest args)
                          (if (or (null args) (equal (car args) ""))
diff --git a/lisp/emacs-lisp/ert.el b/lisp/emacs-lisp/ert.el
index 9cc764d78e0..579e5e0aadc 100644
--- a/lisp/emacs-lisp/ert.el
+++ b/lisp/emacs-lisp/ert.el
@@ -298,8 +298,8 @@ It should only be stopped when ran from inside ert--run-test-internal."
            (error `(signal ',(car err) ',(cdr err))))))
     (cond
      ((or (atom form) (ert--special-operator-p (car form)))
-      (let ((value (cl-gensym "value-")))
-        `(let ((,value (cl-gensym "ert-form-evaluation-aborted-")))
+      (let ((value (gensym "value-")))
+        `(let ((,value (gensym "ert-form-evaluation-aborted-")))
            ,(funcall inner-expander
                      `(setq ,value ,form)
                      `(list ',whole :form ',form :value ,value)
@@ -312,10 +312,10 @@ It should only be stopped when ran from inside ert--run-test-internal."
                        (and (consp fn-name)
                             (eql (car fn-name) 'lambda)
                             (listp (cdr fn-name)))))
-        (let ((fn (cl-gensym "fn-"))
-              (args (cl-gensym "args-"))
-              (value (cl-gensym "value-"))
-              (default-value (cl-gensym "ert-form-evaluation-aborted-")))
+        (let ((fn (gensym "fn-"))
+              (args (gensym "args-"))
+              (value (gensym "value-"))
+              (default-value (gensym "ert-form-evaluation-aborted-")))
           `(let* ((,fn (function ,fn-name))
                   (,args (condition-case err
                              (let ((signal-hook-function #'ert--should-signal-hook))
@@ -357,7 +357,7 @@ FORM-DESCRIPTION-FORM before it has called INNER-FORM."
   (ert--expand-should-1
    whole form
    (lambda (inner-form form-description-form value-var)
-     (let ((form-description (cl-gensym "form-description-")))
+     (let ((form-description (gensym "form-description-")))
        `(let (,form-description)
           ,(funcall inner-expander
                     `(unwind-protect
@@ -435,8 +435,8 @@ failed."
    `(should-error ,form ,@keys)
    form
    (lambda (inner-form form-description-form value-var)
-     (let ((errorp (cl-gensym "errorp"))
-           (form-description-fn (cl-gensym "form-description-fn-")))
+     (let ((errorp (gensym "errorp"))
+           (form-description-fn (gensym "form-description-fn-")))
        `(let ((,errorp nil)
               (,form-description-fn (lambda () ,form-description-form)))
           (condition-case -condition-
diff --git a/lisp/emacs-lisp/generator.el b/lisp/emacs-lisp/generator.el
index c96b400809b..fe5d2d0728f 100644
--- a/lisp/emacs-lisp/generator.el
+++ b/lisp/emacs-lisp/generator.el
@@ -86,10 +86,7 @@
 (defvar cps--cleanup-function nil)
 
 (defmacro cps--gensym (fmt &rest args)
-  ;; Change this function to use `cl-gensym' if you want the generated
-  ;; code to be easier to read and debug.
-  ;; (cl-gensym (apply #'format fmt args))
-  `(progn (ignore ,@args) (make-symbol ,fmt)))
+  `(gensym (format ,fmt ,@args)))
 
 (defvar cps--dynamic-wrappers '(identity)
   "List of transformer functions to apply to atomic forms we
diff --git a/lisp/emacs-lisp/gv.el b/lisp/emacs-lisp/gv.el
index a8b8974cb4f..42b1c216956 100644
--- a/lisp/emacs-lisp/gv.el
+++ b/lisp/emacs-lisp/gv.el
@@ -431,7 +431,7 @@ The return value is the last VAL in the list.
            ;; code is large, but otherwise results in more efficient code.
            `(if ,test ,(gv-get then do)
               ,@(macroexp-unprogn (gv-get (macroexp-progn else) do)))
-         (let ((v (make-symbol "v")))
+         (let ((v (gensym "v")))
            (macroexp-let2 nil
                gv `(if ,test ,(gv-letplace (getter setter) then
                                 `(cons (lambda () ,getter)
@@ -456,7 +456,7 @@ The return value is the last VAL in the list.
                                     (gv-get (macroexp-progn (cdr branch)) do)))
                            (gv-get (car branch) do)))
                        branches))
-         (let ((v (make-symbol "v")))
+         (let ((v (gensym "v")))
            (macroexp-let2 nil
                gv `(cond
                     ,@(mapcar
diff --git a/lisp/emacs-lisp/inline.el b/lisp/emacs-lisp/inline.el
index ce46f66aef8..cf8e2f22d88 100644
--- a/lisp/emacs-lisp/inline.el
+++ b/lisp/emacs-lisp/inline.el
@@ -218,7 +218,7 @@ After VARS is handled, BODY is evaluated in the new environment."
     `(let* ((,bsym ())
             (,listvar (mapcar (lambda (e)
                                 (if (macroexp-copyable-p e) e
-                                  (let ((v (make-symbol "v")))
+                                  (let ((v (gensym "v")))
                                     (push (list v e) ,bsym)
                                     v)))
                               ,listvar)))
diff --git a/lisp/emacs-lisp/pcase.el b/lisp/emacs-lisp/pcase.el
index 253b60e7534..5935845743d 100644
--- a/lisp/emacs-lisp/pcase.el
+++ b/lisp/emacs-lisp/pcase.el
@@ -213,7 +213,7 @@ Emacs Lisp manual for more information and examples."
 (defmacro pcase-exhaustive (exp &rest cases)
   "The exhaustive version of `pcase' (which see)."
   (declare (indent 1) (debug pcase))
-  (let* ((x (make-symbol "x"))
+  (let* ((x (gensym "x"))
          (pcase--dontwarn-upats (cons x pcase--dontwarn-upats)))
     (pcase--expand
      ;; FIXME: Could we add the FILE:LINE data in the error message?
@@ -304,7 +304,7 @@ any kind of error."
   (declare (indent 1) (debug ((pcase-PAT form) body)))
   (if (pcase--trivial-upat-p (car spec))
       `(dolist ,spec ,@body)
-    (let ((tmpvar (make-symbol "x")))
+    (let ((tmpvar (gensym "x")))
       `(dolist (,tmpvar ,@(cdr spec))
          (pcase-let* ((,(car spec) ,tmpvar))
            ,@body)))))
@@ -715,7 +715,7 @@ MATCH is the pattern that needs to be matched, of the form:
            (call (progn
                    (when (memq arg vs)
                      ;; `arg' is shadowed by `env'.
-                     (let ((newsym (make-symbol "x")))
+                     (let ((newsym (gensym "x")))
                        (push (list newsym arg) env)
                        (setq arg newsym)))
                    (if (functionp fun)
@@ -842,7 +842,7 @@ Otherwise, it defers to REST which is a list of branches of the form
         ;; A upat of the form (app FUN PAT)
         (pcase--mark-used sym)
         (let* ((fun (nth 1 upat))
-               (nsym (make-symbol "x"))
+               (nsym (gensym "x"))
                (body
                 ;; We don't change `matches' to reuse the newly computed value,
                 ;; because we assume there shouldn't be such redundancy in there.
diff --git a/lisp/subr.el b/lisp/subr.el
index 2ad52f6a638..ebb8b53b502 100644
--- a/lisp/subr.el
+++ b/lisp/subr.el
@@ -280,6 +280,20 @@ without silencing all errors."
 
 ;;;; Basic Lisp functions.
 
+(defvar gensym-counter 0
+  "Number used to construct the name of the next symbol created by `gensym'.")
+
+(defun gensym (&optional prefix)
+  "Return a new uninterned symbol.
+The name is made by appending `gensym-counter' to PREFIX.
+PREFIX can be a string, and defaults to \"G\".
+If PREFIX is a number, it replaces the value of `gensym-counter'."
+  (let ((pfix (if (stringp prefix) prefix "G"))
+        (num (if (integerp prefix) prefix
+               (prog1 gensym-counter
+                 (setq gensym-counter (1+ gensym-counter))))))
+    (make-symbol (format "%s%d" pfix num))))
+
 (defun ignore (&rest _ignore)
   "Do nothing and return nil.
 This function accepts any number of arguments, but ignores them."