bug#56110: 27+; switching from line-mode to char-mode

[Michael Heerdegen]

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

> > That works - but I fail to understand why a simple `let' doesn't suffice
> > (which works as well):
>
> Depends if you want to have to think about what other code does or
> not.

I want.  The initial revision by Richard already looks like

#+begin_src emacs-lisp
(unwind-protect
    (progn
      (setq term-input-sender (symbol-function 'term-send-string))
      (end-of-line)
      (term-send-input))
  (setq term-input-sender save-input-sender))
#+end_src

I checked (using variable watchers) that when I replace
unwind-protect+setq with let, the executed code doesn't leave the scope
of the let.  So why was it written like that?  `term-input-sender' has a
buffer local binding (it already had in the initial revision from 1994)
- but the current buffer is not changed in between.

Did `let' back then not work with buffer-local bindings - or what could
have been the intention to avoid `let'?

> If you don't, then `let` is not the same: e.g. if some other code uses
> `add/remove-function` on that variable within your `let`, their changes
> will be lost when your `let` ends.

Yeah, such things - but I don't think anything like this is crucial
here.


Thanks,

Michael.