New function flatten-tree

Co-authored-by: Basil L. Contovounesios <contovob@tcd.ie>

* doc/lispref/lists.texi: Document `flatten-tree'.

* lisp/progmodes/js.el (js--maybe-join):
* lisp/printing.el (pr-switches):
* lisp/lpr.el (lpr-print-region):
* lisp/gnus/nnimap.el (nnimap-find-wanted-parts):
* lisp/gnus/message.el (message-talkative-question):
* lisp/gnus/gnus-sum.el (gnus-remove-thread)
(gnus-thread-highest-number, gnus-thread-latest-date):
* lisp/eshell/esh-util.el (eshell-flatten-and-stringify):
* lisp/eshell/esh-opt.el (eshell-eval-using-options):
* lisp/eshell/esh-ext.el (eshell-external-command):
* lisp/eshell/em-xtra.el (eshell/expr):
* lisp/eshell/em-unix.el (eshell/rm, eshell-mvcpln-template)
(eshell/cat, eshell/make, eshell-poor-mans-grep, eshell-grep)
(eshell/du, eshell/time, eshell/diff, eshell/locate):
* lisp/eshell/em-tramp.el (eshell/su, eshell/sudo):
* lisp/eshell/em-term.el (eshell-exec-visual):
* lisp/eshell/em-dirs.el (eshell-dirs-substitute-cd, eshell/cd):
* lisp/eshell/em-basic.el (eshell/printnl):
Use new flatten-tree.

* lisp/progmodes/js.el (js--flatten-list):
* lisp/lpr.el (lpr-flatten-list):
* lisp/gnus/message.el (message-flatten-list):
* lisp/eshell/esh-util.el (eshell-flatten-list):
Obsolete in favor of Emacs-wide `flatten-tree'.

* lisp/subr.el (flatten-list): Alias to `flatten-tree' for
discoverability.

* lisp/subr.el (flatten-tree): New defun.

* test/lisp/subr-tests.el (subr-tests-flatten-tree): New test.

1 files changed, 11 insertions, 11 deletions

diff --git a/lisp/eshell/em-unix.el b/lisp/eshell/em-unix.el
index 3aecebc2ebf..e46e1c417d4 100644
--- a/lisp/eshell/em-unix.el
+++ b/lisp/eshell/em-unix.el
@@ -231,7 +231,7 @@ Otherwise, Emacs will attempt to use rsh to invoke du on the remote machine."
 This is implemented to call either `delete-file', `kill-buffer',
 `kill-process', or `unintern', depending on the nature of the
 argument."
-  (setq args (eshell-flatten-list args))
+  (setq args (flatten-tree args))
   (eshell-eval-using-options
    "rm" args
    '((?h "help" nil nil "show this usage screen")
@@ -481,7 +481,7 @@ Remove the DIRECTORY(ies), if they are empty.")
 	 (error "%s: missing destination file or directory" ,command))
      (if (= len 1)
 	 (nconc args '(".")))
-     (setq args (eshell-stringify-list (eshell-flatten-list args)))
+     (setq args (eshell-stringify-list (flatten-tree args)))
      (if (and ,(not (equal command "ln"))
 	      (string-match eshell-tar-regexp (car (last args)))
 	      (or (> (length args) 2)
@@ -606,7 +606,7 @@ with `--symbolic'.  When creating hard links, each TARGET must exist.")
   "Implementation of cat in Lisp.
 If in a pipeline, or the file is not a regular file, directory or
 symlink, then revert to the system's definition of cat."
-  (setq args (eshell-stringify-list (eshell-flatten-list args)))
+  (setq args (eshell-stringify-list (flatten-tree args)))
   (if (or eshell-in-pipeline-p
 	  (catch 'special
 	    (dolist (arg args)
@@ -670,7 +670,7 @@ Fallback to standard make when called synchronously."
 	(compile (concat "make " (eshell-flatten-and-stringify args))))
     (throw 'eshell-replace-command
 	   (eshell-parse-command "*make" (eshell-stringify-list
-					  (eshell-flatten-list args))))))
+					  (flatten-tree args))))))
 
 (put 'eshell/make 'eshell-no-numeric-conversions t)
 
@@ -705,7 +705,7 @@ available..."
 	  (erase-buffer)
 	  (occur-mode)
 	  (let ((files (eshell-stringify-list
-			(eshell-flatten-list (cdr args))))
+			(flatten-tree (cdr args))))
 		(inhibit-redisplay t)
 		string)
 	    (when (car args)
@@ -750,11 +750,11 @@ external command."
 	(throw 'eshell-replace-command
 	       (eshell-parse-command (concat "*" command)
 				     (eshell-stringify-list
-				      (eshell-flatten-list args))))
+				      (flatten-tree args))))
       (let* ((args (mapconcat 'identity
 			      (mapcar 'shell-quote-argument
 				      (eshell-stringify-list
-				       (eshell-flatten-list args)))
+				       (flatten-tree args)))
 			      " "))
 	     (cmd (progn
 		    (set-text-properties 0 (length args)
@@ -876,7 +876,7 @@ external command."
 (defun eshell/du (&rest args)
   "Implementation of \"du\" in Lisp, passing ARGS."
   (setq args (if args
-		 (eshell-stringify-list (eshell-flatten-list args))
+		 (eshell-stringify-list (flatten-tree args))
 	       '(".")))
   (let ((ext-du (eshell-search-path "du")))
     (if (and ext-du
@@ -976,7 +976,7 @@ Show wall-clock time elapsed during execution of COMMAND.")
 	    (eshell-parse-command (car time-args)
 ;;; https://lists.gnu.org/r/bug-gnu-emacs/2007-08/msg00205.html
 				  (eshell-stringify-list
-				   (eshell-flatten-list (cdr time-args))))))))
+				   (flatten-tree (cdr time-args))))))))
 
 (defun eshell/whoami (&rest _args)
   "Make \"whoami\" Tramp aware."
@@ -1000,7 +1000,7 @@ Show wall-clock time elapsed during execution of COMMAND.")
 
 (defun eshell/diff (&rest args)
   "Alias \"diff\" to call Emacs `diff' function."
-  (let ((orig-args (eshell-stringify-list (eshell-flatten-list args))))
+  (let ((orig-args (eshell-stringify-list (flatten-tree args))))
     (if (or eshell-plain-diff-behavior
 	    (not (and (eshell-interactive-output-p)
 		      (not eshell-in-pipeline-p)
@@ -1056,7 +1056,7 @@ Show wall-clock time elapsed during execution of COMMAND.")
 	       (string-match "^-" (car args))))
       (throw 'eshell-replace-command
 	     (eshell-parse-command "*locate" (eshell-stringify-list
-					      (eshell-flatten-list args))))
+					      (flatten-tree args))))
     (save-selected-window
       (let ((locate-history-list (list (car args))))
 	(locate-with-filter (car args) (cadr args))))))