bug#60102: Move gv-expander of substring to cl-lib

bug#60102: Move gv-expander of substring to cl-lib

[Stefan Monnier via Bug reports for GNU Emacs, the Swiss army knife of text editors]

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Tags: patch

Tags: patch

The `gv-expander` of `substring` uses the `cl--set-substring` function
that's defined only in `cl-lib`, so currently, you can compile

    (setf (substring ...) ...)

without requiring `cl-lib` but at run time it will tend to signal
a `void-function` error.
We could autoload `cl--set-substring`, but I think a better choice is to
move this `gv-expander` to `cl-lib.el`.

There are 2 other place definitions in `gv.el` which similarly rely on
helper functions defined in `cl-lib` (namely `buffer-substring` and
`frame-visible-p`) which we could move as well, but since we marked
those as obsolete anyway I think we can "let them die" where they are,
with their quirks left alone.  If you feel otherwise, I can update the
patch to move them to `cl-lib.el` as well.


        Stefan


 In GNU Emacs 30.0.50 (build 1, x86_64-pc-linux-gnux32, GTK+ Version
 3.24.35, cairo version 1.16.0) of 2022-12-09 built on alfajor
Repository revision: b134e7e6abf18286d38e1b589f0fdae523cf1e73
Repository branch: work
Windowing system distributor 'The X.Org Foundation', version 11.0.12101003
System Description: Debian GNU/Linux bookworm/sid

Configured using:
 'configure -C --enable-checking --enable-check-lisp-object-type --with-modules --with-cairo --with-tiff=ifavailable
 'CFLAGS=-Wall -g3 -Og -Wno-pointer-sign'
 PKG_CONFIG_PATH=/home/monnier/lib/pkgconfig'


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diff --git a/lisp/emacs-lisp/cl-lib.el b/lisp/emacs-lisp/cl-lib.el
index b83b44974d3..ceb5c21baf1 100644
--- a/lisp/emacs-lisp/cl-lib.el
+++ b/lisp/emacs-lisp/cl-lib.el
@@ -170,6 +170,17 @@ cl--set-substring
 	  val
 	  (and (< end (length str)) (substring str end))))
 
+(gv-define-expander substring
+  (lambda (do place from &optional to)
+    (gv-letplace (getter setter) place
+      (macroexp-let2* nil ((start from) (end to))
+        (funcall do `(substring ,getter ,start ,end)
+                 (lambda (v)
+                   (macroexp-let2 nil v v
+                     `(progn
+                        ,(funcall setter `(cl--set-substring
+                                           ,getter ,start ,end ,v))
+                        ,v))))))))
 
 ;;; Blocks and exits.
 
diff --git a/lisp/emacs-lisp/gv.el b/lisp/emacs-lisp/gv.el
index 11251d7a963..29cfca9cb62 100644
--- a/lisp/emacs-lisp/gv.el
+++ b/lisp/emacs-lisp/gv.el
@@ -815,17 +815,5 @@ eq
                      ((eq ,getter ,val) ,(funcall setter `(not ,val))))))))))
 (make-obsolete-generalized-variable 'eq nil "29.1")
 
-(gv-define-expander substring
-  (lambda (do place from &optional to)
-    (gv-letplace (getter setter) place
-      (macroexp-let2* nil ((start from) (end to))
-        (funcall do `(substring ,getter ,start ,end)
-                 (lambda (v)
-                   (macroexp-let2 nil v v
-                     `(progn
-                        ,(funcall setter `(cl--set-substring
-                                           ,getter ,start ,end ,v))
-                        ,v))))))))
-
 (provide 'gv)
 ;;; gv.el ends here

bug#60102: Move gv-expander of substring to cl-lib

[Eli Zaretskii]

> Date: Thu, 15 Dec 2022 15:12:06 -0500
> From:  Stefan Monnier via "Bug reports for GNU Emacs,
>  the Swiss army knife of text editors" <bug-gnu-emacs@gnu.org>
> 
> The `gv-expander` of `substring` uses the `cl--set-substring` function
> that's defined only in `cl-lib`, so currently, you can compile
> 
>     (setf (substring ...) ...)
> 
> without requiring `cl-lib` but at run time it will tend to signal
> a `void-function` error.
> We could autoload `cl--set-substring`, but I think a better choice is to
> move this `gv-expander` to `cl-lib.el`.
> 
> There are 2 other place definitions in `gv.el` which similarly rely on
> helper functions defined in `cl-lib` (namely `buffer-substring` and
> `frame-visible-p`) which we could move as well, but since we marked
> those as obsolete anyway I think we can "let them die" where they are,
> with their quirks left alone.  If you feel otherwise, I can update the
> patch to move them to `cl-lib.el` as well.

Is the patch for master or for the release branch?  I think it should
go to master.

Thanks.

bug#60102: Move gv-expander of substring to cl-lib

[Stefan Monnier via Bug reports for GNU Emacs, the Swiss army knife of text editors]

> Is the patch for master or for the release branch?

Definitely not for the release branch, no.
So I take it you think it's OK for `master`, thanks.


        Stefan

bug#60102: Move gv-expander of substring to cl-lib

[Stefan Kangas]

Stefan Monnier <monnier@iro.umontreal.ca> writes:

>> Is the patch for master or for the release branch?
>
> Definitely not for the release branch, no.
> So I take it you think it's OK for `master`, thanks.

It seems like this patch was never installed?  Should it be?

bug#60102: Move gv-expander of substring to cl-lib

[Stefan Monnier via Bug reports for GNU Emacs, the Swiss army knife of text editors]

>>> Is the patch for master or for the release branch?
>> Definitely not for the release branch, no.
>> So I take it you think it's OK for `master`, thanks.
> It seems like this patch was never installed?  Should it be?

Indeed, thanks, pushed,


        Stefan

bug#60102: Move gv-expander of substring to cl-lib

[Juri Linkov]

> The `gv-expander` of `substring` uses the `cl--set-substring` function
> that's defined only in `cl-lib`, so currently, you can compile
>
>     (setf (substring ...) ...)
>
> without requiring `cl-lib` but at run time it will tend to signal
> a `void-function` error.
> We could autoload `cl--set-substring`, but I think a better choice is to
> move this `gv-expander` to `cl-lib.el`.

I tried your patch by evaluating `(tab-bar-make-keymap-1)`,
but it still fails with:

Debugger entered--Lisp error: (void-function cl--set-substring)
  cl--set-substring(#("*scratch* x" 0 9 ...
  tab-bar-auto-width(((sep-1 menu-item " " ignore) (current-tab menu-item #("*scratch* x" 0 9 ...
  tab-bar-make-keymap-1()
  (progn (tab-bar-make-keymap-1))
  elisp--eval-last-sexp(nil)
  eval-last-sexp(nil)
  funcall-interactively(eval-last-sexp nil)
  command-execute(eval-last-sexp)

OTOH, autoloading `cl--set-substring` fixes this error.