Customize eshell redirection to buffer

Question

In eshell I can redirect the output of a command (foo) to a buffer (bar) by inputting:

foo > #<buffer bar>

I want to customize this syntax the following way:

foo > #bar

Is it possible to customize it? How?

Details emacs version: GNU Emacs 24.3.1 (x86_64-redhat-linux-gnu, GTK+ Version 3.22.10) of 2017-09-20 on c1bm.rdu2.centos.org

Answer 1

To redirect to a buffer, use #<buffer buffer-name>, since Emacs 24.4, you can also use the shorthand #<buffer-name>. For example,

echo hello >>> #<buffer *scratch*>
echo world >>> #<*scratch*>

It looks like it is possible to customize the syntax via the hook eshell-parse-argument-hook, such as supporting #buffer-name as well. Here is my attempt,

(defun eshell-parse-my-special-reference ()
  (when (and (not eshell-current-argument)
             (not eshell-current-quoted)
             ;; Don't overwrite `eshell-parse-special-reference'
             (not (looking-at "#<\\(\\(buffer\\|process\\)\\s-\\)?"))
             (looking-at "#\\(\\S-+\\)")
             (match-string 1))
    (goto-char (match-end 0)) ;; Go to the end of the match.
    (list 'get-buffer-create (match-string 1))))

(add-hook 'eshell-parse-argument-hook #'eshell-parse-my-special-reference)

and the following worked as expected

echo foobar >>> #*scratch*

Answer 2

May not be a direct answer to your problem. But you can use key binding C-c M-b to insert the buffer name at the point. With fido-mode enabled, these key binding help me easily choose the buffer name from the mini-buffer and insert in the form which eshell understands. See Useful Keybindings section of masteringemacs-mastering-eshell for more details.