62 lines
2.3 KiB
Text
62 lines
2.3 KiB
Text
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;;;;;
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title: C-d to close eshell
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tags: eshell, emacs, elisp, config
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date: 2013-08-17 02:25
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format: md
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;;;;;
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One of the "tricks" that I have learned to use when working with
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terminals is using `C-d` to close them, or when working on a TTY
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logout. It somehow grew to the extent that if I can't use it, I get
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annoyed, like with `eshell`.
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I have customized `ansi-term` to immediately close its buffer after the
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shell quits. This makes it very easy to start an `ansi-term`, which I've
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bound to `C-c t`, run a quick command (perhaps `make`, or similar), `C-d`,
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and I'm out. I want that for my `eshell` too.
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There are a few conditions that I want met before the buffer is
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killed, though.
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1. Since `eshell` is an Emacs mode like any other, `C-d` is usually used
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to forward-kill characters, I don't want to lose this.
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2. I only want it to quit when the line of input is empty.
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The following piece of code make sure these conditions are met.
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1. It interactively calls `delete-char`, which keeps keybindings like
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`C-4 C-d` to delete 4 characters working.
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2. It catches the error condition which is signaled whenever
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`delete-char` can't do it's job (like when there's nothing left to
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delete in the buffer).
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3. It checks to make sure that the signaled error is the `end-of-buffer`
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error. I don't want to kill the buffer if I try to delete more
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characters than are in the buffer because I feel that could cause
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irritating surprises.
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4. It checks of the cursor is at the `eshell` prompt. This, combined
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with only responding to the `end-of-buffer` error, makes sure we're
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on an empty line and not just at the end of the input. Sometimes
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keys are pressed at the wrong time and I don't want to have to
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re-type a command just because I was being an idiot.
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5. If the right conditions aren't met, signal the error again so I can
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see what's going on.
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``` emacs-lisp
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(defun eshell-C-d ()
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"Either call `delete-char' interactively or quit."
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(interactive)
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(condition-case err
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(call-interactively #'delete-char)
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(error (if (and (eq (car err) 'end-of-buffer)
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(looking-back eshell-prompt-regexp))
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(kill-buffer)
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(signal (car err) (cdr err))))))
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```
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I then bind this to `C-d` in eshell.
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``` emacs-lisp
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(add-hook 'eshell-mode-hook
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(lambda () (local-set-key (kbd "C-d") #'eshell-C-d)))
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```
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