(global-set-key) vs (define-key)

(global-set-key) vs (define-key)

[Daniel Corbe]

I'm trying to extend eshell so I can use it to manage routers and
switches.  This necessitates changing a few important key-bindings that
equipment manufacturers tend to use.

The problem with the code below is ? works; however, both Ctrl-Z and TAB
stay bound to their original key bindings.

If I use global-set-key instead, TAB and Ctrl-Z do what they're supposed
to do.

I have a suspicion that (define-key) is not allowed to override global
bindings.  Is that true?  If so, what should I be using instead?

(define-derived-mode router-mode eshell-mode "Router"
  "Some key bindings and tools to make dealing with routers/switches easier."

  (define-key eshell-mode-map "?" 'router-mode-help-key)
  (define-key eshell-mode-map (kbd "C-z") 'router-mode-end-key)
  (define-key eshell-mode-map (kbd "TAB") 'self-insert-command))

(defun router-mode-help-key ()
  "Defines what happens when a user hits the ? key."
  (interactive)
  (insert "?")
  (eshell-send-input nil nil t))

(defun router-mode-end-key ()
  "This sends Ctrl-Z along to the shell."
  (interactive)
  (eshell-kill-input)
  (insert "end")
  (eshell-send-input))

RE: (global-set-key) vs (define-key)

[Drew Adams]

> I have a suspicion that (define-key) is not allowed to override
> global bindings.  Is that true?

No.  `define-key' binds a key in the keymap you provide it as a
parameter.  `global-set-key' binds a key in the keymap that is
the value of variable `global-map'.

So these are equivalent:

(global-set-key KEY COMMAND)
(define-key global-map KEY COMMAND)

(`C-h f' is your friend, as is `C-h r i...')

Re: (global-set-key) vs (define-key)

[Michael Heerdegen]

Daniel Corbe <corbe@corbe.net> writes:

> I have a suspicion that (define-key) is not allowed to override global
> bindings.  Is that true?  If so, what should I be using instead?

What do you mean with "global-bindings"?  Probably not bindings in
`global-map', because `define-key' can of course bind keys in
`global-map'.


> (define-derived-mode router-mode eshell-mode "Router"
>   "Some key bindings and tools to make dealing with routers/switches
> easier."
>
>   (define-key eshell-mode-map "?" 'router-mode-help-key)
>   (define-key eshell-mode-map (kbd "C-z") 'router-mode-end-key)
>   (define-key eshell-mode-map (kbd "TAB") 'self-insert-command))

This will modify `eshell-mode-map', the map used by eshell-mode.  This
is probably not what you want.  Better use a separate map, it set
`eshell-mode-map' as parent map to inherit from it.


Michael.

Re: (global-set-key) vs (define-key)

[Daniel Corbe]

Michael Heerdegen <michael_heerdegen@web.de> writes:

> Daniel Corbe <corbe@corbe.net> writes:
>>
>>   (define-key eshell-mode-map "?" 'router-mode-help-key)
>>   (define-key eshell-mode-map (kbd "C-z") 'router-mode-end-key)
>>   (define-key eshell-mode-map (kbd "TAB") 'self-insert-command))
>
> This will modify `eshell-mode-map', the map used by eshell-mode.  This
> is probably not what you want.  Better use a separate map, it set
> `eshell-mode-map' as parent map to inherit from it.

Thanks.  This fixed my issue.  The key bindings work perfectly now.

>
>
> Michael.