Re: [PATCH] Proposal: new syntax for eshell-buffer-shorthand (related: bug#19391)

[Samer Masterson <samer@samertm.com>]

Eli Zaretskii <eliz@gnu.org> writes:

> Could you please send the patch in the form equivalent to "diff -w" (I
> hope Git allows that)?  It's hard to read a large patch where most of
> the lines "changed" just due to whitespace.

My bad, I've attached the diff with whitespace ignored. What's the
process for getting write access to the Emacs repository? If it's
easier, I can install the change after you review it.

Thanks for the review.

-s

Diff below:

diff --git a/etc/NEWS b/etc/NEWS
index 48c3a2a5..9c9f13f 100644
--- a/etc/NEWS
+++ b/etc/NEWS
@@ -659,6 +659,12 @@ command line's password prompt.
 *** The new built-in command `clear' can scroll window contents out of sight.
 If provided with an optional non-nil argument, the scrollback contents will be cleared.
 
+*** New buffer syntax '#<buffer-name>', which is equivalent to
+'#<buffer buffer-name>'.  This shorthand makes interacting with
+buffers from eshell more convenient.  Custom variable
+`eshell-buffer-shorthand', which has been broken for a while, has been
+removed.
+
 ** Browse-url
 
 *** Support for the Conkeror web browser.
diff --git a/lisp/eshell/esh-arg.el b/lisp/eshell/esh-arg.el
index a5f697f..49ba727 100644
--- a/lisp/eshell/esh-arg.el
+++ b/lisp/eshell/esh-arg.el
@@ -357,22 +357,31 @@ after are both returned."
 	  (goto-char (1+ end)))))))
 
 (defun eshell-parse-special-reference ()
-  "Parse a special syntax reference, of the form '#<type arg>'."
-  (if (and (not eshell-current-argument)
+  "Parse a special syntax reference, of the form '#<args>'.
+
+args           := `type' `whitespace' `arbitrary-args' | `arbitrary-args'
+type           := \"buffer\" or \"process\"
+arbitrary-args := any string of characters.
+
+If the form has no 'type', the syntax is parsed as if 'type' were
+\"buffer\"."
+  (when (and (not eshell-current-argument)
              (not eshell-current-quoted)
-	   (looking-at "#<\\(buffer\\|process\\)\\s-"))
+             (looking-at "#<\\(\\(buffer\\|process\\)\\s-\\)?"))
     (let ((here (point)))
-	(goto-char (match-end 0))
-	(let* ((buffer-p (string= (match-string 1) "buffer"))
+      (goto-char (match-end 0)) ;; Go to the end of the match.
+      (let ((buffer-p (if (match-string 1)
+                          (string= (match-string 2) "buffer")
+                        t)) ;; buffer-p is non-nil by default.
             (end (eshell-find-delimiter ?\< ?\>)))
-	  (if (not end)
-	      (throw 'eshell-incomplete ?\<)
+        (when (not end)
+          (throw 'eshell-incomplete ?\<))
         (if (eshell-arg-delimiter (1+ end))
             (prog1
                 (list (if buffer-p 'get-buffer-create 'get-process)
                       (buffer-substring-no-properties (point) end))
               (goto-char (1+ end)))
-	      (ignore (goto-char here))))))))
+          (ignore (goto-char here)))))))
 
 (defun eshell-parse-delimiter ()
   "Parse an argument delimiter, which is essentially a command operator."
diff --git a/lisp/eshell/esh-io.el b/lisp/eshell/esh-io.el
index 7dfc39f..dc731bc 100644
--- a/lisp/eshell/esh-io.el
+++ b/lisp/eshell/esh-io.el
@@ -31,6 +31,18 @@
 ;; consistent with most shells.  Therefore, only unique features are
 ;; mentioned here.
 ;;
+;;;_* Redirect to a Buffer or Process
+;;
+;; Buffers and processes can be named with '#<buffer buffer-name>' and
+;; '#<process process-name>', respectively. As a shorthand,
+;; '#<buffer-name>' without the explicit "buffer" arg is equivalent to
+;; '#<buffer buffer-name>'.
+;;
+;;   echo hello > #<buffer *scratch*> # Overwrite '*scratch*' with 'hello'.
+;;   echo hello > #<*scratch*>        # Same as the command above.
+;;
+;;   echo hello > #<process shell> # Pipe "hello" into the shell process.
+;;
 ;;;_* Insertion
 ;;
 ;; To insert at the location of point in a buffer, use '>>>':
@@ -98,19 +110,6 @@ other buffers) ."
   :type 'integer
   :group 'eshell-io)
 
-(defcustom eshell-buffer-shorthand nil
-  "If non-nil, a symbol name can be used for a buffer in redirection.
-If nil, redirecting to a buffer requires buffer name syntax.  If this
-variable is set, redirection directly to Lisp symbols will be
-impossible.
-
-Example:
-
-  echo hello > '*scratch*  ; works if `eshell-buffer-shorthand' is t
-  echo hello > #<buffer *scratch*>  ; always works"
-  :type 'boolean
-  :group 'eshell-io)
-
 (defcustom eshell-print-queue-size 5
   "The size of the print queue, for doing buffered printing.
 This is basically a speed enhancement, to avoid blocking the Lisp code
@@ -355,21 +354,14 @@ it defaults to `insert'."
 		   (goto-char (point-max))))
 	    (point-marker))))))
 
-   ((or (bufferp target)
-	(and (boundp 'eshell-buffer-shorthand)
-	     (symbol-value 'eshell-buffer-shorthand)
-	     (symbolp target)
-	     (not (memq target '(t nil)))))
-    (let ((buf (if (bufferp target)
-		   target
-		 (get-buffer-create
-		  (symbol-name target)))))
-      (with-current-buffer buf
+
+   ((bufferp target)
+    (with-current-buffer target
       (cond ((eq mode 'overwrite)
              (erase-buffer))
             ((eq mode 'append)
              (goto-char (point-max))))
-	(point-marker))))
+      (point-marker)))
 
    ((functionp target) nil)