; Merge from master.

1 files changed, 37 insertions, 142 deletions

diff --git a/lisp/emacs-lisp/subr-x.el b/lisp/emacs-lisp/subr-x.el
index 7ad4e9ba2ab..9cd793d05c5 100644
--- a/lisp/emacs-lisp/subr-x.el
+++ b/lisp/emacs-lisp/subr-x.el
@@ -81,116 +81,6 @@ Note how the single `-' got converted into a list before
 threading."
   (declare (indent 0) (debug thread-first))
   `(internal--thread-argument nil ,@forms))
-
-(defsubst internal--listify (elt)
-  "Wrap ELT in a list if it is not one.
-If ELT is of the form ((EXPR)), listify (EXPR) with a dummy symbol."
-  (cond
-   ((symbolp elt) (list elt elt))
-   ((null (cdr elt))
-    (list (make-symbol "s") (car elt)))
-   (t elt)))
-
-(defsubst internal--check-binding (binding)
-  "Check BINDING is properly formed."
-  (when (> (length binding) 2)
-    (signal
-     'error
-     (cons "`let' bindings can have only one value-form" binding)))
-  binding)
-
-(defsubst internal--build-binding-value-form (binding prev-var)
-  "Build the conditional value form for BINDING using PREV-VAR."
-  (let ((var (car binding)))
-    `(,var (and ,prev-var ,(cadr binding)))))
-
-(defun internal--build-binding (binding prev-var)
-  "Check and build a single BINDING with PREV-VAR."
-  (thread-first
-    binding
-    internal--listify
-    internal--check-binding
-    (internal--build-binding-value-form prev-var)))
-
-(defun internal--build-bindings (bindings)
-  "Check and build conditional value forms for BINDINGS."
-  (let ((prev-var t))
-    (mapcar (lambda (binding)
-              (let ((binding (internal--build-binding binding prev-var)))
-                (setq prev-var (car binding))
-                binding))
-            bindings)))
-
-(defmacro if-let* (varlist then &rest else)
-  "Bind variables according to VARLIST and evaluate THEN or ELSE.
-This is like `if-let' but doesn't handle a VARLIST of the form
-\(SYMBOL SOMETHING) specially."
-  (declare (indent 2)
-           (debug ((&rest [&or symbolp (symbolp form) (form)])
-                   body)))
-  (if varlist
-      `(let* ,(setq varlist (internal--build-bindings varlist))
-         (if ,(caar (last varlist))
-             ,then
-           ,@else))
-    `(let* () ,then)))
-
-(defmacro when-let* (varlist &rest body)
-  "Bind variables according to VARLIST and conditionally evaluate BODY.
-This is like `when-let' but doesn't handle a VARLIST of the form
-\(SYMBOL SOMETHING) specially."
-  (declare (indent 1) (debug if-let*))
-  (list 'if-let* varlist (macroexp-progn body)))
-
-(defmacro and-let* (varlist &rest body)
-  "Bind variables according to VARLIST and conditionally evaluate BODY.
-Like `when-let*', except if BODY is empty and all the bindings
-are non-nil, then the result is non-nil."
-  (declare (indent 1) (debug if-let*))
-  (let (res)
-    (if varlist
-        `(let* ,(setq varlist (internal--build-bindings varlist))
-           (when ,(setq res (caar (last varlist)))
-             ,@(or body `(,res))))
-      `(let* () ,@(or body '(t))))))
-
-;;;###autoload
-(defmacro if-let (spec then &rest else)
-  "Bind variables according to SPEC and evaluate THEN or ELSE.
-Evaluate each binding in turn, as in `let*', stopping if a
-binding value is nil.  If all are non-nil return the value of
-THEN, otherwise the last form in ELSE.
-
-Each element of SPEC is a list (SYMBOL VALUEFORM) that binds
-SYMBOL to the value of VALUEFORM.  An element can additionally be
-of the form (VALUEFORM), which is evaluated and checked for nil;
-i.e. SYMBOL can be omitted if only the test result is of
-interest.  It can also be of the form SYMBOL, then the binding of
-SYMBOL is checked for nil.
-
-As a special case, interprets a SPEC of the form \(SYMBOL SOMETHING)
-like \((SYMBOL SOMETHING)).  This exists for backward compatibility
-with an old syntax that accepted only one binding."
-  (declare (indent 2)
-           (debug ([&or (symbolp form)  ; must be first, Bug#48489
-                        (&rest [&or symbolp (symbolp form) (form)])]
-                   body)))
-  (when (and (<= (length spec) 2)
-             (not (listp (car spec))))
-    ;; Adjust the single binding case
-    (setq spec (list spec)))
-  (list 'if-let* spec then (macroexp-progn else)))
-
-;;;###autoload
-(defmacro when-let (spec &rest body)
-  "Bind variables according to SPEC and conditionally evaluate BODY.
-Evaluate each binding in turn, stopping if a binding value is nil.
-If all are non-nil, return the value of the last form in BODY.
-
-The variable list SPEC is the same as in `if-let'."
-  (declare (indent 1) (debug if-let))
-  (list 'if-let spec (macroexp-progn body)))
-
 (defsubst hash-table-empty-p (hash-table)
   "Check whether HASH-TABLE is empty (has 0 elements)."
   (zerop (hash-table-count hash-table)))
@@ -320,12 +210,6 @@ than this function."
      (end (substring string (- (length string) length)))
      (t (substring string 0 length)))))
 
-;;;###autoload
-(defun string-lines (string &optional omit-nulls)
-  "Split STRING into a list of lines.
-If OMIT-NULLS, empty lines will be removed from the results."
-  (split-string string "\n" omit-nulls))
-
 (defun string-pad (string length &optional padding start)
   "Pad STRING to LENGTH using PADDING.
 If PADDING is nil, the space character is used.  If not nil, it
@@ -414,32 +298,6 @@ and return the value found in PLACE instead."
                ,(funcall setter val)
                ,val)))))
 
-;;;###autoload
-(defun ensure-empty-lines (&optional lines)
-  "Ensure that there are LINES number of empty lines before point.
-If LINES is nil or omitted, ensure that there is a single empty
-line before point.
-
-If called interactively, LINES is given by the prefix argument.
-
-If there are more than LINES empty lines before point, the number
-of empty lines is reduced to LINES.
-
-If point is not at the beginning of a line, a newline character
-is inserted before adjusting the number of empty lines."
-  (interactive "p")
-  (unless (bolp)
-    (insert "\n"))
-  (let ((lines (or lines 1))
-        (start (save-excursion
-                 (if (re-search-backward "[^\n]" nil t)
-                     (+ (point) 2)
-                   (point-min)))))
-    (cond
-     ((> (- (point) start) lines)
-      (delete-region (point) (- (point) (- (point) start lines))))
-     ((< (- (point) start) lines)
-      (insert (make-string (- lines (- (point) start)) ?\n))))))
 
 ;;;###autoload
 (defun string-pixel-width (string)
@@ -558,6 +416,43 @@ this defaults to the current buffer."
         (error "No process selected"))
       process)))
 
+(defmacro with-buffer-unmodified-if-unchanged (&rest body)
+  "Like `progn', but change buffer-modified status only if buffer text changes.
+If the buffer was unmodified before execution of BODY, and
+buffer text after execution of BODY is identical to what it was
+before, ensure that buffer is still marked unmodified afterwards.
+For example, the following won't change the buffer's modification
+status:
+
+  (with-buffer-unmodified-if-unchanged
+    (insert \"a\")
+    (delete-char -1))
+
+Note that only changes in the raw byte sequence of the buffer text,
+as stored in the internal representation, are monitored for the
+purpose of detecting the lack of changes in buffer text.  Any other
+changes that are normally perceived as \"buffer modifications\", such
+as changes in text properties, `buffer-file-coding-system', buffer
+multibyteness, etc. -- will not be noticed, and the buffer will still
+be marked unmodified, effectively ignoring those changes."
+  (declare (debug t) (indent 0))
+  (let ((hash (gensym))
+        (buffer (gensym)))
+    `(let ((,hash (and (not (buffer-modified-p))
+                       (buffer-hash)))
+           (,buffer (current-buffer)))
+       (prog1
+           (progn
+             ,@body)
+         ;; If we didn't change anything in the buffer (and the buffer
+         ;; was previously unmodified), then flip the modification status
+         ;; back to "unchanged".
+         (when (and ,hash (buffer-live-p ,buffer))
+           (with-current-buffer ,buffer
+             (when (and (buffer-modified-p)
+                        (equal ,hash (buffer-hash)))
+               (restore-buffer-modified-p nil))))))))
+
 (provide 'subr-x)
 
 ;;; subr-x.el ends here