;;; calc-yank.el --- kill-ring functionality for Calc  -*- lexical-binding:t -*-

;; Copyright (C) 1990-1993, 2001-2023 Free Software Foundation, Inc.

;; Author: David Gillespie <daveg@synaptics.com>

;; This file is part of GNU Emacs.

;; GNU Emacs is free software: you can redistribute it and/or modify
;; it under the terms of the GNU General Public License as published by
;; the Free Software Foundation, either version 3 of the License, or
;; (at your option) any later version.

;; GNU Emacs is distributed in the hope that it will be useful,
;; but WITHOUT ANY WARRANTY; without even the implied warranty of
;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
;; GNU General Public License for more details.

;; You should have received a copy of the GNU General Public License
;; along with GNU Emacs.  If not, see <https://www.gnu.org/licenses/>.

;;; Commentary:

;;; Code:

;; This file is autoloaded from calc-ext.el.

(require 'calc-ext)
(require 'calc-macs)

;;; Kill ring commands.

(defun calc-kill (nn &optional no-delete)
  (interactive "P")
  (if (eq major-mode 'calc-mode)
      (calc-wrapper
       (calc-force-refresh)
       (calc-set-command-flag 'no-align)
       (let ((num (max (calc-locate-cursor-element (point)) 1))
	     (n (prefix-numeric-value nn)))
	 (if (< n 0)
	     (progn
	       (if (eobp)
		   (setq num (1- num)))
	       (setq num (- num n)
		     n (- n))))
         (calc-check-stack num)
	 (let ((stuff (calc-top-list n (- num n -1))))
	   (calc-cursor-stack-index num)
           (unless calc-kill-line-numbering
             (re-search-forward "\\=[0-9]+:\\s-+" (line-end-position) t))
	   (let ((first (point)))
	     (calc-cursor-stack-index (- num n))
	     (if (null nn)
		 (backward-char 1))   ; don't include newline for raw C-k
	     (copy-region-as-kill first (point))
	     (if (not no-delete)
		 (calc-pop-stack n (- num n -1))))
	   (setq calc-last-kill (cons (car kill-ring) stuff)))))
    (kill-line nn)))

(defun calc-force-refresh ()
  (if (or calc-executing-macro calc-display-dirty)
      (let ((calc-executing-macro nil))
	(calc-refresh))))

(defun calc-locate-cursor-element (pt)
  (save-excursion
    (goto-char (point-max))
    (calc-locate-cursor-scan (- calc-stack-top) calc-stack pt)))

(defun calc-locate-cursor-scan (n stack pt)
  (if (or (<= (point) pt)
	  (null stack))
      n
    (forward-line (- (nth 1 (car stack))))
    (calc-locate-cursor-scan (1+ n) (cdr stack) pt)))

(defun calc-kill-region (top bot &optional no-delete)
  (interactive "r")
  (if (eq major-mode 'calc-mode)
      (calc-wrapper
       (calc-force-refresh)
       (calc-set-command-flag 'no-align)
       (let* ((top-num (calc-locate-cursor-element top))
              (top-pos (save-excursion
                         (calc-cursor-stack-index top-num)
                         (point)))
	      (bot-num (calc-locate-cursor-element (1- bot)))
              (bot-pos (save-excursion
                         (calc-cursor-stack-index (max 0 (1- bot-num)))
                         (point)))
	      (num (- top-num bot-num -1)))
	 (copy-region-as-kill top-pos bot-pos)
	 (setq calc-last-kill (cons (car kill-ring)
				    (calc-top-list num bot-num)))
	 (if (not no-delete)
	     (calc-pop-stack num bot-num))))
    (if no-delete
	(copy-region-as-kill top bot)
      (kill-region top bot))))

(defun calc-copy-as-kill (n)
  (interactive "P")
  (calc-kill n t))

(defun calc-copy-region-as-kill (top bot)
  (interactive "r")
  (calc-kill-region top bot t))

(defun math-number-regexp (radix-num)
  "Return a regexp which will match a Calc number base RADIX-NUM."
  (let* ((digit-range
          (cond
           ;; radix 2 to 10
           ((and (<= 2 radix-num)
                 (>= 10 radix-num))
            (concat "[0-"
                    (number-to-string (1- radix-num))
                    "]"))
           ;; radix 11
           ((= 11 radix-num) "[0-9aA]")
           ;; radix 12+
           (t
            (concat "[0-9"
                    "a-" (format "%c" (+ (- ?a 11) radix-num))
                    "A-" (format "%c" (+ (- ?A 11) radix-num))
                    "]"))))
         (integer-regexp (concat digit-range "+"))
         (decimal-regexp (concat digit-range "+\\." digit-range "*")))
    (concat
     " *\\("
     ;; "e" notation
     "[-_+]?" decimal-regexp "[eE][-+]?[0-9]+"
     "\\|"
     "[-_+]?" integer-regexp "[eE][-+]?[0-9]+"
     "\\|"
     ;; Integer+fractions
     "[-_+]?" integer-regexp "*[:/]" integer-regexp "[:/]" integer-regexp
     "\\|"
     ;; Fractions
     "[-_+]?" integer-regexp "[:/]" integer-regexp
     "\\|"
     ;; Decimal point
     "[-_+]?" decimal-regexp
     "\\|"
     ;; Integers
     "[-_+]?" integer-regexp
     "\\) *\\(\n\\|\\'\\)")))

;; This function uses calc-last-kill if possible to get an exact result,
;; otherwise it just parses the yanked string.
;;;###autoload
(defun calc-yank-internal (radix thing-raw)
  "Internal common implementation for yank functions.

This function is used by both `calc-yank' and `calc-yank-mouse-primary'."
  (calc-wrapper
   (calc-pop-push-record-list
    0 "yank"
    (let* (radix-num
           radix-notation
           valid-num-regexp
           (thing
            (if (or (null radix)
                    ;; Match examples: -2#10, 10\n(10#10,01)
                    (string-match-p "^[-(]*[0-9]\\{1,2\\}#" thing-raw))
                thing-raw
              (progn
                (if (listp radix)
                    (progn
                      (setq radix-num
                            (read-number
                             "Set radix for yanked content (2-36): "))
                      (when (not (and (integerp radix-num)
                                      (<= 2 radix-num)
                                      (>= 36 radix-num)))
                        (error (concat "The radix has to be an "
                                       "integer between 2 and 36."))))
                  (setq radix-num
                        (cond ((eq radix 2) 2)
                              ((eq radix 8) 8)
                              ((eq radix 0) 10)
                              ((eq radix 6) 16)
                              (t (message
                                  (concat "No radix prepended "
                                          "for invalid *numeric* "
                                          "prefix %0d.")
                                  radix)
                                 nil))))
                (if radix-num
                    (progn
                      (setq radix-notation
                            (concat (number-to-string radix-num) "#"))
                      (setq valid-num-regexp
                            (math-number-regexp radix-num))
                      ;; Ensure that the radix-notation is prefixed
                      ;; correctly even for multi-line yanks like below,
                      ;;   111
                      ;;   1111
                      (replace-regexp-in-string
                       valid-num-regexp
                       (concat radix-notation "\\&")
                       thing-raw))
                  thing-raw)))))
      (if (eq (car-safe calc-last-kill) thing-raw)
          (cdr calc-last-kill)
        (if (stringp thing)
            (let ((val (math-read-exprs (calc-clean-newlines thing))))
              (if (eq (car-safe val) 'error)
                  (progn
                    (setq val (math-read-exprs thing))
                    (if (eq (car-safe val) 'error)
                        (error "Bad format in yanked data")
                      val))
                val))))))))

;;;###autoload
(defun calc-yank-mouse-primary (radix)
  "Yank the current primary selection into the Calculator buffer.
See `calc-yank' for details about RADIX."
  (interactive "P")
  (if (or select-enable-primary
          select-enable-clipboard)
      (calc-yank-internal radix (gui-get-primary-selection))
    ;; Yank from the kill ring.
    (calc-yank radix)))

;;;###autoload
(defun calc-yank (radix)
  "Yank a value into the Calculator buffer.

Valid numeric prefixes for RADIX: 0, 2, 6, 8
No radix notation is prepended for any other numeric prefix.

If RADIX is 2, prepend \"2#\"  - Binary.
If RADIX is 8, prepend \"8#\"  - Octal.
If RADIX is 0, prepend \"10#\" - Decimal.
If RADIX is 6, prepend \"16#\" - Hexadecimal.

If RADIX is a non-nil list (created using \\[universal-argument]), the user
will be prompted to enter the radix in the minibuffer.

If RADIX is nil or if the yanked string already has a calc radix prefix, the
yanked string will be passed on directly to the Calculator buffer without any
alteration."
  (interactive "P")
  (calc-yank-internal radix (current-kill 0 t)))

;;; The Calc set- and get-register commands are modified versions of functions
;;; in register.el

(defvar calc-register-alist nil
  "Alist of elements (NAME . (TEXT . CALCVAL)).
NAME is a character (a number).
TEXT and CALCVAL are the TEXT and internal structure of stack entries.")

(defun calc-set-register (register text calcval)
  "Set the contents of the Calc register REGISTER to (TEXT . CALCVAL),
as well as set the contents of the Emacs register REGISTER to TEXT."
  (set-register register text)
  (setf (alist-get register calc-register-alist) (cons text calcval)))

(defun calc-get-register (reg)
  "Return the CALCVAL portion of the contents of the Calc register REG,
unless the TEXT portion doesn't match the contents of the Emacs register REG,
in which case either return the contents of the Emacs register (if it is
text or a number) or nil."
  (let ((cval (cdr (assq reg calc-register-alist)))
        (val (cdr (assq reg register-alist))))
    (cond
     ((stringp val)
      (if (and (stringp (car cval))
               (string= (car cval) val))
          (cdr cval)
        val))
     ((numberp val) (number-to-string val)))))

(defun calc-copy-to-register (register start end &optional delete-flag)
  "Copy the lines in the region into register REGISTER.
With prefix arg, delete as well.

Interactively, reads the register using `register-read-with-preview'."
  (interactive (list (register-read-with-preview "Copy to register: ")
		     (region-beginning) (region-end)
		     current-prefix-arg))
  (if (eq major-mode 'calc-mode)
      (let* ((top-num (calc-locate-cursor-element start))
             (top-pos (save-excursion
                        (calc-cursor-stack-index top-num)
                        (point)))
             (bot-num (calc-locate-cursor-element (1- end)))
             (bot-pos (save-excursion
                        (calc-cursor-stack-index (max 0 (1- bot-num)))
                        (point)))
             (num (- top-num bot-num -1))
             (str (buffer-substring top-pos bot-pos)))
        (calc-set-register register str (calc-top-list num bot-num))
        (if delete-flag
            (calc-wrapper
             (calc-pop-stack num bot-num))))
    (copy-to-register register start end delete-flag)))

(defun calc-insert-register (register)
  "Insert the contents of register REGISTER.

Interactively, reads the register using `register-read-with-preview'."
  (interactive (list (register-read-with-preview "Insert register: ")))
  (if (eq major-mode 'calc-mode)
      (let ((val (calc-get-register register)))
        (calc-wrapper
         (calc-pop-push-record-list
          0 "insr"
          (if (not val)
              (error "Bad format in register data")
            (if (consp val)
                val
              (let ((nval (math-read-exprs (calc-clean-newlines val))))
                (if (eq (car-safe nval) 'error)
                    (progn
                      (setq nval (math-read-exprs val))
                      (if (eq (car-safe nval) 'error)
                          (error "Bad format in register data")
                        nval))
                  nval)))))))
    (insert-register register)))

(defun calc-add-to-register (register start end prepend delete-flag)
  "Add the lines in the region to register REGISTER.
If PREPEND is non-nil, add them to the beginning of the register,
otherwise the end.  If DELETE-FLAG is non-nil, also delete the region."
  (let* ((top-num (calc-locate-cursor-element start))
         (top-pos (save-excursion
                    (calc-cursor-stack-index top-num)
                    (point)))
         (bot-num (calc-locate-cursor-element (1- end)))
         (bot-pos (save-excursion
                    (calc-cursor-stack-index (max 0 (1- bot-num)))
                    (point)))
         (num (- top-num bot-num -1))
         (str (buffer-substring top-pos bot-pos))
         (calcval (calc-top-list num bot-num))
         (cval (cdr (assq register calc-register-alist))))
    (if (not cval)
        (calc-set-register register str calcval)
      (if prepend
          (calc-set-register
           register
           (concat str (car cval))
           (append calcval (cdr cval)))
        (calc-set-register
         register
         (concat (car cval) str)
         (append (cdr cval) calcval))))
    (if delete-flag
        (calc-wrapper
         (calc-pop-stack num bot-num)))))

(defun calc-append-to-register (register start end &optional delete-flag)
  "Copy the lines in the region to the end of register REGISTER.
With prefix arg, also delete the region.

Interactively, reads the register using `register-read-with-preview'."
  (interactive (list (register-read-with-preview "Append to register: ")
		     (region-beginning) (region-end)
		     current-prefix-arg))
  (if (eq major-mode 'calc-mode)
      (calc-add-to-register register start end nil delete-flag)
    (append-to-register register start end delete-flag)))

(defun calc-prepend-to-register (register start end &optional delete-flag)
  "Copy the lines in the region to the beginning of register REGISTER.
With prefix arg, also delete the region.

Interactively, reads the register using `register-read-with-preview'."
  (interactive (list (register-read-with-preview "Prepend to register: ")
		     (region-beginning) (region-end)
		     current-prefix-arg))
  (if (eq major-mode 'calc-mode)
      (calc-add-to-register register start end t delete-flag)
    (prepend-to-register register start end delete-flag)))



(defun calc-clean-newlines (s)
  (cond

   ;; Omit leading/trailing whitespace
   ((or (string-match "\\`[ \n\r]+\\([^\001]*\\)\\'" s)
	(string-match "\\`\\([^\001]*\\)[ \n\r]+\\'" s))
    (calc-clean-newlines (math-match-substring s 1)))

   ;; Convert newlines to commas
   ((string-match "\\`\\(.*\\)[\n\r]+\\([^\001]*\\)\\'" s)
    (calc-clean-newlines (concat (math-match-substring s 1) ","
				 (math-match-substring s 2))))

   (t s)))


(defun calc-do-grab-region (top bot arg)
  (when (memq major-mode '(calc-mode calc-trail-mode))
    (error "This command works only in a regular text buffer"))
  (let* ((from-buffer (current-buffer))
	 (calc-was-started (get-buffer-window "*Calculator*"))
	 (single nil)
	 data vals) ;; pos
    (if arg
	(if (consp arg)
	    (setq single t)
	  (setq arg (prefix-numeric-value arg))
	  (if (= arg 0)
              (setq top (line-beginning-position)
                    bot (line-end-position))
	    (save-excursion
	      (setq top (point))
	      (forward-line arg)
	      (if (> arg 0)
		  (setq bot (point))
		(setq bot top
		      top (point)))))))
    (setq data (buffer-substring top bot))
    (calc)
    (if single
	(setq vals (math-read-expr data))
      (setq vals (math-read-expr (concat "[" data "]")))
      (and (eq (car-safe vals) 'vec)
	   (= (length vals) 2)
	   (eq (car-safe (nth 1 vals)) 'vec)
	   (setq vals (nth 1 vals))))
    (if (eq (car-safe vals) 'error)
	(progn
	  (if calc-was-started
	      (pop-to-buffer from-buffer)
	    (calc-quit t)
	    (switch-to-buffer from-buffer))
	  (goto-char top)
	  (forward-char (+ (nth 1 vals) (if single 0 1)))
	  (error (nth 2 vals))))
    (calc-slow-wrapper
     (calc-enter-result 0 "grab" vals))))


(defun calc-do-grab-rectangle (top bot arg &optional reduce)
  (and (memq major-mode '(calc-mode calc-trail-mode))
       (error "This command works only in a regular text buffer"))
  (let* ((col1 (save-excursion (goto-char top) (current-column)))
	 (col2 (save-excursion (goto-char bot) (current-column)))
	 (from-buffer (current-buffer))
	 (calc-was-started (get-buffer-window "*Calculator*"))
	 data mat vals lnum pt pos)
    (if (= col1 col2)
	(save-excursion
	  (unless (= col1 0)
	    (error "Point and mark must be at beginning of line, or define a rectangle"))
	  (goto-char top)
	  (while (< (point) bot)
	    (setq pt (point))
	    (forward-line 1)
	    (setq data (cons (buffer-substring pt (1- (point))) data)))
	  (setq data (nreverse data)))
      (setq data (extract-rectangle top bot)))
    (calc)
    (setq mat (list 'vec)
	  lnum 0)
    (when arg
      (setq arg (if (consp arg) 0 (prefix-numeric-value arg))))
    (while data
      (if (natnump arg)
	  (progn
	    (if (= arg 0)
		(setq arg 1000000))
	    (setq pos 0
		  vals (list 'vec))
	    (let ((w (length (car data)))
		  j v)
	      (while (< pos w)
		(setq j (+ pos arg)
		      v (if (>= j w)
			    (math-read-expr (substring (car data) pos))
			  (math-read-expr (substring (car data) pos j))))
		(if (eq (car-safe v) 'error)
		    (setq vals v w 0)
		  (setq vals (nconc vals (list v))
			pos j)))))
	(if (string-match "\\` *-?[0-9][0-9]?[0-9]?[0-9]?[0-9]?[0-9]? *\\'"
			  (car data))
	    (setq vals (list 'vec (string-to-number (car data))))
	  (if (and (null arg)
		   (string-match "[[{][^][{}]*[]}]" (car data)))
	      (setq pos (match-beginning 0)
		    vals (math-read-expr (math-match-substring (car data) 0)))
	    (let ((s (if (string-match
			  "\\`\\([0-9]+:[ \t]\\)?\\(.*[^, \t]\\)[, \t]*\\'"
			  (car data))
			 (math-match-substring (car data) 2)
		       (car data))))
	      (setq pos -1
		    vals (math-read-expr (concat "[" s "]")))
	      (if (eq (car-safe vals) 'error)
		  (let ((v2 (math-read-expr s)))
		    (unless (eq (car-safe v2) 'error)
		      (setq vals (list 'vec v2)))))))))
      (if (eq (car-safe vals) 'error)
	  (progn
	    (if calc-was-started
		(pop-to-buffer from-buffer)
	      (calc-quit t)
	      (switch-to-buffer from-buffer))
	    (goto-char top)
	    (forward-line lnum)
	    (forward-char (+ (nth 1 vals) (min col1 col2) pos))
	    (error (nth 2 vals))))
      (unless (equal vals '(vec))
	(setq mat (cons vals mat)))
      (setq data (cdr data)
	    lnum (1+ lnum)))
    (calc-slow-wrapper
     (if reduce
	 (calc-enter-result 0 "grb+" (list reduce '(var add var-add)
					   (nreverse mat)))
       (calc-enter-result 0 "grab" (nreverse mat))))))


(defun calc-copy-to-buffer (nn)
  "Copy the top of stack into an editing buffer."
  (interactive "P")
  (let ((thebuf (and (not (memq major-mode '(calc-mode calc-trail-mode)))
		     (current-buffer)))
	(movept nil)
	oldbuf newbuf)
    (calc-wrapper
     (save-excursion
       (calc-force-refresh)
       (let ((n (prefix-numeric-value nn))
	     (eat-lnums calc-line-numbering)
	     (big-offset (if (eq calc-language 'big) 1 0))
	     top bot)
	 (setq oldbuf (current-buffer)
	       newbuf (or thebuf
			  (calc-find-writable-buffer (buffer-list) 0)
			  (calc-find-writable-buffer (buffer-list) 1)
			  (error "No other buffer")))
	 (cond ((and (or (null nn)
			 (consp nn))
		     (= (calc-substack-height 0)
			(- (1- (calc-substack-height 1)) big-offset)))
		(calc-cursor-stack-index 1)
		(if (looking-at
		     (if calc-line-numbering "[0-9]+: *[^ \n]" " *[^ \n]"))
		    (goto-char (1- (match-end 0))))
		(setq eat-lnums nil
		      top (point))
		(calc-cursor-stack-index 0)
		(setq bot (- (1- (point)) big-offset)))
	       ((> n 0)
		(calc-cursor-stack-index n)
		(setq top (point))
		(calc-cursor-stack-index 0)
		(setq bot (- (point) big-offset)))
	       ((< n 0)
		(calc-cursor-stack-index (- n))
		(setq top (point))
		(calc-cursor-stack-index (1- (- n)))
		(setq bot (point)))
	       (t
		(goto-char (point-min))
		(forward-line 1)
		(setq top (point))
		(calc-cursor-stack-index 0)
		(setq bot (point))))
	 (with-current-buffer newbuf
	   (if (consp nn)
	       (kill-region (region-beginning) (region-end)))
	   (push-mark (point) t)
	   (if (and overwrite-mode (not (consp nn)))
	       (calc-overwrite-string (with-current-buffer oldbuf
					(buffer-substring top bot))
				      eat-lnums)
	     (or (bolp) (setq eat-lnums nil))
	     (insert-buffer-substring oldbuf top bot)
	     (and eat-lnums
		  (let ((n 1))
		    (while (and (> (point) (mark))
				(progn
				  (forward-line -1)
				  (>= (point) (mark))))
		      (delete-char 4)
		      (setq n (1+ n)))
		    (forward-line n))))
	   (when thebuf
	     (setq movept (point)))
	   (when (get-buffer-window (current-buffer))
	     (set-window-point (get-buffer-window (current-buffer))
			       (point)))))))
    (when movept
      (goto-char movept))
    (when (and (consp nn)
	       (not thebuf))
      (calc-quit t)
      (switch-to-buffer newbuf))))

(defun calc-overwrite-string (str eat-lnums)
  (when (string-match "\n\\'" str)
    (setq str (substring str 0 -1)))
  (when eat-lnums
    (setq str (substring str 4)))
  (if (and (string-match "\\`[-+]?[0-9.]+\\(e-?[0-9]+\\)?\\'" str)
	   (looking-at "[-+]?[0-9.]+\\(e-?[0-9]+\\)?"))
      (progn
	(delete-region (point) (match-end 0))
	(insert str))
    (let ((i 0))
      (while (< i (length str))
	(if (= (setq last-command-event (aref str i)) ?\n)
	    (or (= i (1- (length str)))
		(let ((pt (point)))
		  (end-of-line)
		  (delete-region pt (point))
		  (if (eobp)
		      (insert "\n")
		    (forward-char 1))
		  (if eat-lnums (setq i (+ i 4)))))
	  (self-insert-command 1))
	(setq i (1+ i))))))

;; First, require that buffer is visible and does not begin with "*"
;; Second, require only that it not begin with "*Calc"
(defun calc-find-writable-buffer (buf mode)
  (and buf
       (if (or (string-match "\\`\\( .*\\|\\*Calc.*\\)"
			     (buffer-name (car buf)))
	       (and (= mode 0)
		    (or (string-match "\\`\\*.*" (buffer-name (car buf)))
			(not (get-buffer-window (car buf))))))
	   (calc-find-writable-buffer (cdr buf) mode)
	 (car buf))))


(defun calc-edit (n)
  (interactive "p")
  (calc-slow-wrapper
   (when (eq n 0)
     (setq n (calc-stack-size)))
   (let* (;; (flag nil)
	  (allow-ret (> n 1))
	  (list (math-showing-full-precision
		 (mapcar (if (> n 1)
                             (lambda (x)
                               (math-format-flat-expr x 0))
                           (lambda (x)
                             (if (math-vectorp x) (setq allow-ret t))
                             (math-format-nice-expr x (frame-width))))
			 (if (> n 0)
			     (calc-top-list n)
			   (calc-top-list 1 (- n)))))))
     (calc--edit-mode (lambda () (calc-finish-stack-edit n)) ;; (or flag n)
                      allow-ret)
     (while list
       (insert (car list) "\n")
       (setq list (cdr list)))))
  (calc-show-edit-buffer))

(defun calc-alg-edit (str)
  (calc--edit-mode (lambda () (calc-finish-stack-edit 0)))
  (calc-show-edit-buffer)
  (insert str "\n")
  (backward-char 1)
  (calc-set-command-flag 'do-edit))

(defvar-keymap calc-edit-mode-map
  :doc "Keymap for use by the `calc-edit' command."
  "C-j"     #'calc-edit-finish
  "RET"     #'calc-edit-return
  "C-c C-c" #'calc-edit-finish)

(defvar calc-original-buffer nil)
(defvar calc-return-buffer nil)
(defvar calc-one-window nil)
(defvar calc-edit-handler nil)
(defvar calc-restore-trail nil)
(defvar calc-allow-ret nil)
(defvar calc-edit-top nil)

(put 'calc-edit-mode 'mode-class 'special)
(define-derived-mode calc-edit-mode nil "Calc Edit"
  "Calculator editing mode.  Press RET, LFD, or C-c C-c to finish.
To cancel the edit, simply kill the *Calc Edit* buffer."
  (setq-local buffer-read-only nil)
  (setq-local truncate-lines nil))

(defun calc--edit-mode (handler &optional allow-ret title)
  (unless handler
    (error "This command can be used only indirectly through calc-edit"))
  (let ((oldbuf (current-buffer))
	(buf (get-buffer-create "*Calc Edit*")))
    (set-buffer buf)
    (calc-edit-mode)
    (setq-local calc-original-buffer oldbuf)
    (setq-local calc-return-buffer oldbuf)
    (setq-local calc-one-window (and (one-window-p t) pop-up-windows))
    (setq-local calc-edit-handler handler)
    (setq-local calc-restore-trail (get-buffer-window (calc-trail-buffer)))
    (setq-local calc-allow-ret allow-ret)
    (let ((inhibit-read-only t))
      (erase-buffer))
    (add-hook 'kill-buffer-hook (lambda ()
                                  (let ((calc-edit-handler nil))
                                    (calc-edit-finish t))
                                  (message "(Canceled)"))
              t t)
    (insert (propertize
             (concat
              (or title title "Calc Edit Mode. ")
              (substitute-command-keys "Press \\`C-c C-c'")
              (if allow-ret "" " or RET")
              (substitute-command-keys " to finish, \\`C-x k RET' to cancel.\n\n"))
             'font-lock-face 'italic 'read-only t 'rear-nonsticky t 'front-sticky t))
    (setq-local calc-edit-top (point))))

(defun calc-show-edit-buffer ()
  (let ((buf (current-buffer)))
    (if (and (one-window-p t) pop-up-windows)
	(pop-to-buffer (get-buffer-create "*Calc Edit*"))
      (and calc-embedded-info (get-buffer-window (aref calc-embedded-info 1))
	   (select-window (get-buffer-window (aref calc-embedded-info 1))))
      (switch-to-buffer (get-buffer-create "*Calc Edit*")))
    (setq calc-return-buffer buf)
    (if (and (< (window-width) (frame-width))
	     calc-display-trail)
	(let ((win (get-buffer-window (calc-trail-buffer))))
	  (if win
	      (delete-window win))))
    (set-buffer-modified-p nil)
    (goto-char calc-edit-top)))

(defun calc-edit-return ()
  (interactive)
  (if calc-allow-ret
      (newline)
    (calc-edit-finish)))

;; The variable `calc-edit-disp-trail' is local to `calc-edit-finish', but
;; is used by `calc-finish-selection-edit' and `calc-finish-stack-edit'.
(defvar calc-edit-disp-trail)

(defun calc-edit-finish (&optional keep)
  "Finish `calc-edit' mode.  Parse buffer contents and push them on the stack."
  (interactive "P")
  (message "Working...")
  (or (derived-mode-p 'calc-edit-mode)
      (error "This command is valid only in buffers created by calc-edit"))
  (let ((buf (current-buffer))
	(original calc-original-buffer)
	(return calc-return-buffer)
	(one-window calc-one-window)
	(calc-edit-disp-trail calc-restore-trail))
    (save-excursion
      (when (or (null (buffer-name original))
		(progn
		  (set-buffer original)
		  (not (eq major-mode 'calc-mode))))
	(error "Original calculator buffer has been corrupted")))
    (goto-char calc-edit-top)
    (if (buffer-modified-p)
	(if (functionp calc-edit-handler)
	    (funcall calc-edit-handler)
	  (message "Deprecated handler expression in calc-edit-handler: %S"
	           calc-edit-handler)
	  (eval calc-edit-handler t)))
    (if (and one-window (not (one-window-p t)))
	(delete-window))
    (if (get-buffer-window return)
	(select-window (get-buffer-window return))
      (switch-to-buffer return))
    (if keep
	(bury-buffer buf)
      (kill-buffer buf))
    (if calc-edit-disp-trail
	(calc-wrapper
	 (calc-trail-display 1 t)))
    (message "")))

(defun calc-edit-cancel ()
  "Cancel calc-edit mode.  Ignore the Calc Edit buffer and don't change stack."
  (interactive)
  (let ((calc-edit-handler nil))
    (calc-edit-finish))
  (message "(Canceled)"))

(defun calc-finish-stack-edit (num)
  (let ((buf (current-buffer))
	(str (buffer-substring calc-edit-top (point-max)))
	(start (point))
	pos)
    (if (and (integerp num) (> num 1))
	(while (setq pos (string-match "\n." str))
	  (aset str pos ?\,)))
    (switch-to-buffer calc-original-buffer)
    (let ((vals (let ((calc-language nil)
		      (math-expr-opers (math-standard-ops)))
		  (and (string-match "[^\n\t ]" str)
		       (math-read-exprs str)))))
      (when (eq (car-safe vals) 'error)
	(switch-to-buffer buf)
	(goto-char (+ start (nth 1 vals)))
	(error (nth 2 vals)))
      (calc-wrapper
       (if (symbolp num)
	   (progn
	     (set num (car vals))
	     (calc-refresh-evaltos num))
	 (if calc-edit-disp-trail
	     (calc-trail-display 1 t))
	 (and vals
	      (let ((calc-simplify-mode (if (eq last-command-event ?\C-j)
					    'none
					  calc-simplify-mode)))
		(if (>= num 0)
		    (calc-enter-result num "edit" vals)
		  (calc-enter-result 1 "edit" vals (- num))))))))))

(provide 'calc-yank)

;; Local variables:
;; generated-autoload-file: "calc-loaddefs.el"
;; End:

;;; calc-yank.el ends here