Say how to override a primitive interactive spec

* doc/lispref/internals.texi (Writing Emacs Primitives): Mention that
  the `interactive-form' property can be used to override a primitive
  interactive specification, and refer to the detailed documentation
  for setting that property.

From this thread on Emacs Devel:

  https://lists.gnu.org/archive/html/emacs-devel/2018-03/msg00923.html
  From: Eli Zaretskii
  To: Karl Fogel
  CC: Juri Linkov, Emacs Devel
  Subject: Re: [Emacs-diffs] \
           master b88e7c8: Make transpose-regions interactive (Bug#30343)
  Date: Thu, 29 Mar 2018 14:38:15 +0300
  Message-Id: <834lkzdsd4.fsf@gnu.org>

diff --git a/doc/lispref/internals.texi b/doc/lispref/internals.texi
index e6043357a11a05aaca39bb67af64118a6f2d51b2..25333270c3e61316d2ea62a72a66ed22fce9a794 100644 (file)
--- a/doc/lispref/internals.texi
+++ b/doc/lispref/internals.texi
@@ -743,6 +743,11 @@ DEFUN ("foo", Ffoo, Sfoo, 0, UNEVALLED, 0
 @end group
 @end example
 
+If you wish to override a primitive interactive specification, just
+set the @code{interactive-form} property of the primitive function's
+symbol (@pxref{Using Interactive}).  There is no need to edit C code
+and recompile Emacs.
+
 @item doc
 This is the documentation string.  It uses C comment syntax rather
 than C string syntax because comment syntax requires nothing special