bug#62892: proposal to extend mark-sexp to go forward and backward on command

[Stefan Monnier]

> If this is to be accepted, why not extend it to all like mark functions,
> listed below?  Implementing them should be pretty similar, and you might
> even be able to reuse the same helper for all these variants.  Also, the
> helper function might need to contain a double-dash in its name because
> this is inherently a private function.
>
> - `mark-defun'
> - `mark-page'
> - `mark-paragraph'
> - `mark-word'

Agreed: we should move towards a more orthogonal/composable design,
where the granularity of the operation (char, word, line, sexp,
paragraph, page, defun, ...) and the operation itself (move, mark) and
the direction and all independent such that we can use any combination
of them.

Both at the ELisp level and at the key-binding level.


        Stefan