Re: Is it legal to set `help-char' to nil?

[YE Qianchuan <stool.ye@gmail.com>]

On 04/10/2013 10:49 PM, Michael Heerdegen wrote:
> YE Qianchuan <stool.ye@gmail.com> writes:
>
>> I prefer using C-h to delete backward, thus I mapped C-h to DEL by
>> modifying key-translation-map.  Then set `help-char' to nil to avoid
>> invoking help for a list of commands start by prefix. (I can't find a
>> good enough char to replace it) For example, press C-x C-h to invoke
>> C-x DEL but not to print help message.
>>
>> If it's not legal, are there any workaround?
> Dunno if it's legal.
>
>> If it's legal, then there are bugs in certain modules like term,
>> because doing such thing breaks it.
> In which way?
>
> In term, no matter if `help-char' is bound to 8 or not, I see that C-h
> is bound to the command `term-send-raw' in char-mode.  Or do you use
> line-mode?  In this case, note that C-h is still bound in the
> global-map (which is something different than `help-char'):
Well, I can't even enter term-mode.
I can reproduce it in this way:
1. open emacs without initial files (emacs -Q)
2. eval (setq help-char nil)
3. type M-x term
Then it throw an error: Wrong type argument: characterp, nil.
If you don't have this problem, maybe it's a bug in trunk.
>
> ,----------------------------------------------------------------------
> | ELISP> (lookup-key global-map [?\C-h])
> | help-command
> |
> | ELISP> (symbol-function 'help-command)
> | (keymap
> |  (111 . my-info-org)
> |  (11 . describe-bindings-for-key)
> |  (113 . help-quit)
> |  (118 . describe-variable)
> |  (119 . where-is)
> |  (116 . my-info-tramp)
> |  (115 . describe-syntax)
> |  (114 . info-emacs-manual)
> |  (80 . describe-package)
> |  (112 . finder-by-keyword)
> |  (110 . view-emacs-news)
> |  (109 . describe-mode)
> |  (108 . view-lossage)
> |  (107 . describe-key)
> |  (52 keymap
> |      (105 . info-other-window))
> |  (105 . info)
> |  (104 . view-hello-file)
> |  (103 . my-info-gnus)
> |  (102 . describe-function)
> |  (101 . my-info-elisp)
> |  (100 . apropos-documentation)
> |  (99 . my-info-cl)
> |  (98 . describe-bindings)
> |  (97 . apropos)
> |  (83 . info-lookup-symbol)
> |  (76 . describe-language-environment)
> |  (75 . Info-goto-emacs-key-command-node)
> |  (73 . describe-input-method)
> |  (70 . Info-goto-emacs-command-node)
> |  (67 . describe-coding-system)
> |  (28 . describe-input-method)
> |  (23 . describe-no-warranty)
> |  (20 . view-emacs-todo)
> |  (16 . view-emacs-problems)
> |  (15 . describe-distribution)
> |  (14 . view-emacs-news)
> |  (13 . view-order-manuals)
> |  (6 . view-emacs-FAQ)
> |  (5 . view-external-packages)
> |  (4 . view-emacs-debugging)
> |  (3 . describe-copying)
> |  (1 . about-emacs)
> |  (63 . help-for-help)
> |  (46 . display-local-help)
> |  (f1 . help-for-help)
> |  (help . help-for-help)
> |  (8 . help-for-help))
> `----------------------------------------------------------------------
>
> Of course, you can unbind it.
>
>
> Regards,
>
> Michael.