Re: [Emacs-diffs] master b88e7c8: Make transpose-regions interactive (Bug#30343)

[Charles A. Roelli]

> Date: Wed, 21 Mar 2018 09:22:19 +0200
> From: Eli Zaretskii <address@hidden>
> 
> Here are some reasons why not to make the change:
> 
>   . there's nothing wrong with that code
>   . having it in C doesn't make hacking harder because one can always
>     override functions in Emacs, 

Good point.  Is this written in the Elisp manual anywhere?  I searched
for "override functions" and "override primitives" in the index, but
did not find a result.  We could add a note saying that functions
defined from C can be overridden from Lisp (possibly in (elisp) What
Is a Function).

>                                  and moving the interactive spec to
>     Lisp will still leave the code preloaded anyway

Instead of defining transpose-regions (and its interactive spec) in
Lisp (as the reverted patch did), we could take the current
interactive spec of transpose-regions and use that to make a preloaded
function named "read-two-regions" in simple.el.  That would allow its
reuse by other commands, too.