How can I tweak this elisp function to distinguish between C-d & DEL?

Question

Here's my current function (blindly copy-pasted from a website)

(defun tweakemacs-delete-one-line ()
  "Delete current line."
  (interactive)
  (beginning-of-line)
  (kill-line)
  (kill-line))
(global-set-key (kbd "C-d") 'tweakemacs-delete-one-line)

There are two quirks here that I want to get rid of. 1) This actually rebinds DEL to the same function. I want my DEL to remain "delete one character". 2) There needs to be a condition where it will not double-kill if the line is only a newline character.

Answer 1

To distinguish those two, use the preferred vector syntax for keys:

(global-set-key [delete] 'foo)
(global-set-key [(control d)] 'bar)

As for the second thing, it sounds as if you either want

(setq kill-whole-line t)

or just want to use the function kill-entire-line instead.

Answer 2

I read part of the manual on keybindings, and it said that C-d and <DEL>, like other special keys, are bound. To unbind them you have to explicitly set both of them.

Ultimately, I used this solution:

(global-set-key (kbd "<delete>") 'delete-char)
(global-set-key ([control d]) 'kill-whole-word)