Use a common set of string delimiters for all Eshell predicates/modifiers

* lisp/eshell/em-pred.el (eshell-pred-delimiter-pairs): New variable.
(eshell-get-comparison-modifier-argument)
(eshell-get-numeric-modifier-argument)
(eshell-get-delimited-modifier-argument): New functions...
(eshell-pred-user-or-group, eshell-pred-file-time)
(eshell-pred-file-links, eshell-pred-file-size)
(eshell-pred-substitute, eshell-join-memebers, eshell-split-members):
... and use them here.
(eshell-include-members): Pass 'mod-char' and use
'eshell-get-delimited-modifier-argument'.
(eshell-pred-file-type, eshell-pred-file-mode): Use 'when-let'.
(eshell-modifier-alist): Pass modifier char to
'eshell-include-members'.

* test/lisp/eshell/em-pred-tests.el
(em-pred-test/predicate-delimiters): New test.
(em-pred-test/predicate-uid, em-pred-test/predicate-gid,
em-pred-test/modifier-include, em-pred-test/modifier-exclude): Remove
cases covered by 'em-pred-test/predicate-delimiters'.
(em-pred-test/modifier-substitute): Add test cases for new delimiter
styles.

* doc/misc/eshell.texi (Argument Predication and Modification):
Explain how string parameters are delimited.
(Argument Modifiers): Document some special delimiter behavior with
the 's/PATTERN/REPLACE/' modifier (bug#55204).

* etc/NEWS: Announce this change, and move the
'eshell-eval-using-options' entry to the Eshell section.

1 files changed, 128 insertions, 145 deletions

diff --git a/lisp/eshell/em-pred.el b/lisp/eshell/em-pred.el
index eb5109b82dc..594563554d2 100644
--- a/lisp/eshell/em-pred.el
+++ b/lisp/eshell/em-pred.el
@@ -116,8 +116,8 @@ The format of each entry is
     (?U . (lambda (lst) (mapcar #'upcase lst)))
     (?C . (lambda (lst) (mapcar #'capitalize lst)))
     (?h . (lambda (lst) (mapcar #'file-name-directory lst)))
-    (?i . (eshell-include-members))
-    (?x . (eshell-include-members t))
+    (?i . (eshell-include-members ?i))
+    (?x . (eshell-include-members ?x t))
     (?r . (lambda (lst) (mapcar #'file-name-sans-extension lst)))
     (?e . (lambda (lst) (mapcar #'file-name-extension lst)))
     (?t . (lambda (lst) (mapcar #'file-name-nondirectory lst)))
@@ -219,6 +219,20 @@ FOR LISTS OF ARGUMENTS:
 EXAMPLES:
   *.c(:o)  sorted list of .c files")
 
+(defvar eshell-pred-delimiter-pairs
+  '((?\( . ?\))
+    (?\[ . ?\])
+    (?\< . ?\>)
+    (?\{ . ?\})
+    (?\' . ?\')
+    (?\" . ?\")
+    (?/  . ?/)
+    (?|  . ?|))
+  "A list of delimiter pairs that can be used in argument predicates/modifiers.
+Each element is of the form (OPEN . CLOSE), where OPEN and CLOSE
+are characters representing the opening and closing delimiter,
+respectively.")
+
 (defvar-keymap eshell-pred-mode-map
   "C-c M-q" #'eshell-display-predicate-help
   "C-c M-m" #'eshell-display-modifier-help)
@@ -364,38 +378,68 @@ resultant list of strings."
                  (lambda (file) (funcall pred (file-truename file))))))
   (cons pred funcs))
 
+(defun eshell-get-comparison-modifier-argument (&optional functions)
+  "Starting at point, get the comparison modifier argument, if any.
+These are the -/+ characters, corresponding to `<' and `>',
+respectively.  If no comparison modifier is at point, return `='.
+
+FUNCTIONS, if non-nil, is a list of comparison functions,
+specified as (LESS-THAN GREATER-THAN EQUAL-TO)."
+  (let ((functions (or functions (list #'< #'> #'=))))
+    (if (memq (char-after) '(?- ?+))
+        (prog1
+            (if (eq (char-after) ?-) (nth 0 functions) (nth 1 functions))
+          (forward-char))
+      (nth 2 functions))))
+
+(defun eshell-get-numeric-modifier-argument ()
+  "Starting at point, get the numeric modifier argument, if any.
+If a number is found, update point to just after the number."
+  (when (looking-at "[0-9]+")
+    (prog1
+        (string-to-number (match-string 0))
+      (goto-char (match-end 0)))))
+
+(defun eshell-get-delimited-modifier-argument (&optional chained-p)
+  "Starting at point, get the delimited modifier argument, if any.
+If the character after point is a predicate/modifier
+delimiter (see `eshell-pred-delimiter-pairs', read the value of
+the argument and update point to be just after the closing
+delimiter.
+
+If CHAINED-P is true, then another delimited modifier argument
+will immediately follow this one.  In this case, when the opening
+and closing delimiters are the same, update point to be just
+before the closing delimiter. This allows modifiers like
+`:s/match/repl' to work as expected."
+  (when-let* ((open (char-after))
+              (close (cdr (assoc open eshell-pred-delimiter-pairs)))
+              (end (eshell-find-delimiter open close nil nil t)))
+    (prog1
+        (buffer-substring-no-properties (1+ (point)) end)
+      (goto-char (if (and chained-p (eq open close))
+                     end
+                   (1+ end))))))
+
 (defun eshell-pred-user-or-group (mod-char mod-type attr-index get-id-func)
   "Return a predicate to test whether a file match a given user/group id."
-  (let (ugid open close end)
-    (if (looking-at "[0-9]+")
-        (progn
-          (setq ugid (string-to-number (match-string 0)))
-          (goto-char (match-end 0)))
-      (setq open (char-after))
-      (if (setq close (memq open '(?\( ?\[ ?\< ?\{)))
-          (setq close (car (last '(?\) ?\] ?\> ?\})
-                                 (length close))))
-        (setq close open))
-      (forward-char)
-      (setq end (eshell-find-delimiter open close))
-      (unless end
-        (error "Malformed %s name string for modifier `%c'"
-               mod-type mod-char))
-      (setq ugid
-            (funcall get-id-func (buffer-substring (point) end)))
-      (goto-char (1+ end)))
+  (let ((ugid (eshell-get-numeric-modifier-argument)))
+    (unless ugid
+      (let ((ugname (or (eshell-get-delimited-modifier-argument)
+                        (error "Malformed %s name string for modifier `%c'"
+                               mod-type mod-char))))
+        (setq ugid (funcall get-id-func ugname))))
     (unless ugid
       (error "Unknown %s name specified for modifier `%c'"
              mod-type mod-char))
     (lambda (file)
-      (let ((attrs (file-attributes file)))
-        (if attrs
-            (= (nth attr-index attrs) ugid))))))
+      (when-let ((attrs (file-attributes file)))
+        (= (nth attr-index attrs) ugid)))))
 
 (defun eshell-pred-file-time (mod-char mod-type attr-index)
   "Return a predicate to test whether a file matches a certain time."
   (let* ((quantum 86400)
-         qual when open close end)
+         qual when)
     (when (memq (char-after) '(?M ?w ?h ?m ?s))
       (setq quantum (char-after))
       (cond
@@ -410,36 +454,21 @@ resultant list of strings."
        ((eq quantum ?s)
         (setq quantum 1)))
       (forward-char))
-    (when (memq (char-after) '(?+ ?-))
-      (setq qual (char-after))
-      (forward-char))
-    (if (looking-at "[0-9]+")
-        (progn
-          (setq when (time-since (* (string-to-number (match-string 0))
-                                    quantum)))
-          (goto-char (match-end 0)))
-      (setq open (char-after))
-      (if (setq close (memq open '(?\( ?\[ ?\< ?\{)))
-          (setq close (car (last '(?\) ?\] ?\> ?\})
-                                 (length close))))
-        (setq close open))
-      (forward-char)
-      (setq end (eshell-find-delimiter open close))
-      (unless end
-        (error "Malformed %s time modifier `%c'" mod-type mod-char))
-      (let* ((file (buffer-substring (point) end))
-             (attrs (file-attributes file)))
-        (unless attrs
-          (error "Cannot stat file `%s'" file))
-        (setq when (nth attr-index attrs)))
-      (goto-char (1+ end)))
-    (let ((f (cond ((eq qual ?-) #'time-less-p)
-                     ((eq qual ?+) (lambda (a b) (time-less-p b a)))
-                     (#'time-equal-p))))
-      (lambda (file)
-        (let ((attrs (file-attributes file)))
-          (if attrs
-              (funcall f when (nth attr-index attrs))))))))
+    (setq qual (eshell-get-comparison-modifier-argument
+                (list #'time-less-p
+                      (lambda (a b) (time-less-p b a))
+                      #'time-equal-p)))
+    (if-let ((number (eshell-get-numeric-modifier-argument)))
+        (setq when (time-since (* number quantum)))
+      (let* ((file (or (eshell-get-delimited-modifier-argument)
+                       (error "Malformed %s time modifier `%c'"
+                              mod-type mod-char)))
+             (attrs (or (file-attributes file)
+                        (error "Cannot stat file `%s'" file))))
+        (setq when (nth attr-index attrs))))
+    (lambda (file)
+      (when-let ((attrs (file-attributes file)))
+        (funcall qual when (nth attr-index attrs))))))
 
 (defun eshell-pred-file-type (type)
   "Return a test which tests that the file is of a certain TYPE.
@@ -454,36 +483,23 @@ that `ls -l' will show in the first column of its display."
                  '(?b ?c)
                (list type))))
     (lambda (file)
-      (let ((attrs (eshell-file-attributes (directory-file-name file))))
-        (if attrs
-            (memq (aref (file-attribute-modes attrs) 0) set))))))
+      (when-let ((attrs (eshell-file-attributes (directory-file-name file))))
+        (memq (aref (file-attribute-modes attrs) 0) set)))))
 
 (defsubst eshell-pred-file-mode (mode)
   "Return a test which tests that MODE pertains to the file."
   (lambda (file)
-    (let ((modes (file-modes file 'nofollow)))
-      (if modes
-          (not (zerop (logand mode modes)))))))
+    (when-let ((modes (file-modes file 'nofollow)))
+      (not (zerop (logand mode modes))))))
 
 (defun eshell-pred-file-links ()
   "Return a predicate to test whether a file has a given number of links."
-  (let (qual amount)
-    (when (memq (char-after) '(?- ?+))
-      (setq qual (char-after))
-      (forward-char))
-    (unless (looking-at "[0-9]+")
-      (error "Invalid file link count modifier `l'"))
-    (setq amount (string-to-number (match-string 0)))
-    (goto-char (match-end 0))
-    (let ((f (if (eq qual ?-)
-                 #'<
-               (if (eq qual ?+)
-                   #'>
-                 #'=))))
-      (lambda (file)
-        (let ((attrs (eshell-file-attributes file)))
-          (if attrs
-              (funcall f (file-attribute-link-number attrs) amount)))))))
+  (let ((qual (eshell-get-comparison-modifier-argument))
+        (amount (or (eshell-get-numeric-modifier-argument)
+                    (error "Invalid file link count modifier `l'"))))
+    (lambda (file)
+      (when-let ((attrs (eshell-file-attributes file)))
+          (funcall qual (file-attribute-link-number attrs) amount)))))
 
 (defun eshell-pred-file-size ()
   "Return a predicate to test whether a file is of a given size."
@@ -498,85 +514,52 @@ that `ls -l' will show in the first column of its display."
        ((eq qual ?p)
         (setq quantum 512)))
       (forward-char))
-    (when (memq (char-after) '(?- ?+))
-      (setq qual (char-after))
-      (forward-char))
-    (unless (looking-at "[0-9]+")
-      (error "Invalid file size modifier `L'"))
-    (setq amount (* (string-to-number (match-string 0)) quantum))
-    (goto-char (match-end 0))
-    (let ((f (if (eq qual ?-)
-                 #'<
-               (if (eq qual ?+)
-                   #'>
-                 #'=))))
-      (lambda (file)
-        (let ((attrs (eshell-file-attributes file)))
-          (if attrs
-              (funcall f (file-attribute-size attrs) amount)))))))
+    (setq qual (eshell-get-comparison-modifier-argument))
+    (setq amount (* (or (eshell-get-numeric-modifier-argument)
+                        (error "Invalid file size modifier `L'"))
+                    quantum))
+    (lambda (file)
+      (when-let ((attrs (eshell-file-attributes file)))
+        (funcall qual (file-attribute-size attrs) amount)))))
 
 (defun eshell-pred-substitute (&optional repeat)
   "Return a modifier function that will substitute matches."
-  (let ((delim (char-after))
-        match replace end)
-    (forward-char)
-    (setq end (eshell-find-delimiter delim delim nil nil t)
-          match (buffer-substring-no-properties (point) end))
-    (goto-char (1+ end))
-    (setq end (eshell-find-delimiter delim delim nil nil t)
-          replace (buffer-substring-no-properties (point) end))
-    (goto-char (1+ end))
-    (if repeat
-        (lambda (lst)
-          (mapcar
-           (lambda (str)
-             (replace-regexp-in-string match replace str t))
-           lst))
-      (lambda (lst)
-        (mapcar
-         (lambda (str)
-           (if (string-match match str)
-               (replace-match replace t nil str)
-             (error (concat str ": substitution failed"))))
-         lst)))))
-
-(defun eshell-include-members (&optional invert-p)
-  "Include only Lisp members matching a regexp."
-  (let ((delim (char-after))
-        regexp end)
-    (forward-char)
-    (setq end (eshell-find-delimiter delim delim nil nil t)
-          regexp (buffer-substring-no-properties (point) end))
-    (goto-char (1+ end))
-    (let ((predicates
-           (list (if invert-p
-                     (lambda (elem) (not (string-match regexp elem)))
-                   (lambda (elem) (string-match regexp elem))))))
-      (lambda (lst)
-        (eshell-winnow-list lst nil predicates)))))
+  (let* ((match (or (eshell-get-delimited-modifier-argument t)
+                    (error "Malformed pattern string for modifier `s'")))
+         (replace (or (eshell-get-delimited-modifier-argument)
+                      (error "Malformed replace string for modifier `s'")))
+         (function (if repeat
+                       (lambda (str)
+                         (replace-regexp-in-string match replace str t))
+                     (lambda (str)
+                       (if (string-match match str)
+                           (replace-match replace t nil str)
+                         (error (concat str ": substitution failed")))))))
+    (lambda (lst) (mapcar function lst))))
+
+(defun eshell-include-members (mod-char &optional invert-p)
+  "Include only Lisp members matching a regexp.
+If INVERT-P is non-nil, include only members not matching a regexp."
+  (let* ((regexp (or (eshell-get-delimited-modifier-argument)
+                     (error "Malformed pattern string for modifier `%c'"
+                            mod-char)))
+         (predicates
+          (list (if invert-p
+                    (lambda (elem) (not (string-match regexp elem)))
+                  (lambda (elem) (string-match regexp elem))))))
+    (lambda (lst)
+      (eshell-winnow-list lst nil predicates))))
 
 (defun eshell-join-members ()
   "Return a modifier function that join matches."
-  (let ((delim (char-after))
-        str end)
-    (if (not (memq delim '(?' ?/)))
-        (setq str " ")
-      (forward-char)
-      (setq end (eshell-find-delimiter delim delim nil nil t)
-            str (buffer-substring-no-properties (point) end))
-      (goto-char (1+ end)))
+  (let ((str (or (eshell-get-delimited-modifier-argument)
+                 " ")))
     (lambda (lst)
       (mapconcat #'identity lst str))))
 
 (defun eshell-split-members ()
   "Return a modifier function that splits members."
-  (let ((delim (char-after))
-        sep end)
-    (when (memq delim '(?' ?/))
-      (forward-char)
-      (setq end (eshell-find-delimiter delim delim nil nil t)
-            sep (buffer-substring-no-properties (point) end))
-      (goto-char (1+ end)))
+  (let ((sep (eshell-get-delimited-modifier-argument)))
     (lambda (lst)
       (mapcar
        (lambda (str)