Expand rx definitions inside (not ...)

* lisp/emacs-lisp/rx.el (rx--translate-not):
* test/lisp/emacs-lisp/rx-tests.el (rx-not, rx-def-in-not):
* doc/lispref/searching.texi (Rx Constructs, Extending Rx):

Allow user-defined rx constructs to be expanded inside (not ...)
forms, for better composability (bug#37849).

1 files changed, 3 insertions, 0 deletions

diff --git a/lisp/emacs-lisp/rx.el b/lisp/emacs-lisp/rx.el
index d7677f14443..52a35ffa2a7 100644
--- a/lisp/emacs-lisp/rx.el
+++ b/lisp/emacs-lisp/rx.el
@@ -477,6 +477,9 @@ If NEGATED, negate the sense (thus making it positive)."
      ((eq arg 'word-boundary)
       (rx--translate-symbol
        (if negated 'word-boundary 'not-word-boundary)))
+     ((let ((expanded (rx--expand-def arg)))
+        (and expanded
+             (rx--translate-not negated (list expanded)))))
      (t (error "Illegal argument to rx `not': %S" arg)))))
 
 (defun rx--atomic-regexp (item)