Change typos in comments.

(forms-delete-record, forms--update): Use `delete-region' instead of
`kill-line' to avoid messing around with the kill ring.

Release 2.1 for Emacs 19.19.
(forms--process-format-list): No need to prepend a text item anymore.
(forms--ro-modification-start): Renamed to `forms--iif-start.
(forms--ro-properties): Renamed to `forms--iif-properties'.
(forms--romh): Renamed to `forms--iif-hook'.  Rewritten to use
`insert-in-front-hooks' instead of `modification-hooks'.
(forms--romh-post-command-hook): Renamed to
`forms--iif-post-command-hook'.  Rewritten to use
`insert-in-front-hooks' instead of `modification-hooks'.
(forms--make-format, forms--make-format-elt-using-text-properties):
Use `insert-in-front-hooks' instead of `modification-hooks'.
Remove `forms--electric' code.  Use `front-sticky' and
`rear-nonsticky' text properties to control the insertion of text
between read-only fields.
(forms--show-record): Remove `forms--electric' code.

diff --git a/lisp/forms.el b/lisp/forms.el
index e476e4e..5094b79 100644 (file)
--- a/lisp/forms.el
+++ b/lisp/forms.el
@@ -2,7 +2,7 @@
 ;;; Copyright (C) 1991, 1993 Free Software Foundation, Inc.
 
 ;; Author: Johan Vromans <jv@mh.nl>
-;; Version: 2.0
+;; Version: 2.2
 
 ;; This file is part of GNU Emacs.
 
@@ -26,8 +26,8 @@
 ;;;
 ;;; === Naming conventions
 ;;;
-;;; The names of all variables and functions start with 'form-'.
-;;; Names which start with 'form--' are intended for internal use, and
+;;; The names of all variables and functions start with 'forms-'.
+;;; Names which start with 'forms--' are intended for internal use, and
 ;;; should *NOT* be used from the outside.
 ;;;
 ;;; All variables are buffer-local, to enable multiple forms visits 
@@ -253,7 +253,7 @@
 (provide 'forms)                       ;;; official
 (provide 'forms-mode)                  ;;; for compatibility
 
-(defconst forms-version "2.0"
+(defconst forms-version "2.2"
   "Version of forms-mode implementation.")
 
 (defvar forms-mode-hooks nil
@@ -643,12 +643,9 @@ Commands (prefix with C-c if not in read-only mode):
            (aset forms--elements field-num (1- el)))
          (setq field-num (1+ field-num))
 
-         ;; Make sure the field is preceded by something.
          (if prev-item
              (setq forms-format-list
-                   (append forms-format-list (list prev-item) nil))
-           (setq forms-format-list
-                 (append forms-format-list (list "\n") nil)))
+                   (append forms-format-list (list prev-item) nil)))
          (setq prev-item el))
 
         ;; Try function ...
@@ -680,7 +677,7 @@ Commands (prefix with C-c if not in read-only mode):
          (setq forms-format-list
                (append forms-format-list (list prev-item) nil))
          ;; Append a newline if the last item is a field.
-         ;; This prevents pasrsing problems.
+         ;; This prevents parsing problems.
          ;; Also it makes it possible to insert an empty last field.
          (if (numberp prev-item)
              (setq forms-format-list
@@ -691,74 +688,66 @@ Commands (prefix with C-c if not in read-only mode):
 \f
 ;; Special treatment for read-only segments.
 ;;
-;; If text is inserted after a read-only segment, it inherits the
+;; If text is inserted between two read-only segments, it inherits the
 ;; read-only properties.  This is not what we want.
-;; The modification hook of the last character of the read-only segment
-;; temporarily switches its properties to read-write, so the new
+;; To solve this, read-only segments get the `insert-in-front-hooks'
+;; property set with a function that temporarily switches the properties
+;; of the first character of the segment to read-write, so the new
 ;; text gets the right properties.
-;; The post-command-hook is used to restore the original properties.
-;;
-;; A character category `forms-electric' is used for the characters
-;; that get the modification hook set.  Using a category, it is
-;; possible to globally enable/disable the modification hook.  This is
-;; necessary, since modifying a hook or setting text properties are
-;; considered modifications and would trigger the hooks while building
-;; the forms.
-
-(defvar forms--ro-modification-start nil
+;; The `post-command-hook' is used to restore the original properties.
+
+(defvar forms--iif-start nil
   "Record start of modification command.")
-(defvar forms--ro-properties nil
+(defvar forms--iif-properties nil
   "Original properties of the character being overridden.")
 
-(defun forms--romh (begin end)
-  "`modification-hook' function for forms-electric characters."
+(defun forms--iif-hook (begin end)
+  "`insert-in-front-hooks' function for read-only segments."
 
-  ;; Note start location.
-  (or forms--ro-modification-start
-      (setq forms--ro-modification-start (point)))
+  ;; Note start location.  By making it a marker that points one 
+  ;; character beyond the actual location, it is guaranteed to move 
+  ;; correctly if text is inserted.
+  (or forms--iif-start
+      (setq forms--iif-start (copy-marker (1+ (point)))))
 
-  ;; Fetch current properties.
-  (setq forms--ro-properties 
-       (text-properties-at (1- forms--ro-modification-start)))
-
-  ;; Disarm modification hook.
-  (setplist 'forms--electric nil)
+  ;; Check if there is special treatment required.
+  (if (or (<= forms--iif-start 2)
+         (get-text-property (- forms--iif-start 2)
+                            'read-only))
+      (progn
+       ;; Fetch current properties.
+       (setq forms--iif-properties 
+             (text-properties-at (1- forms--iif-start)))
 
-  ;; Replace them.
-  (let ((inhibit-read-only t))
-    (set-text-properties 
-     (1- forms--ro-modification-start) forms--ro-modification-start
-     (list 'face forms--rw-face)))
+       ;; Replace them.
+       (let ((inhibit-read-only t))
+         (set-text-properties 
+          (1- forms--iif-start) forms--iif-start
+          (list 'face forms--rw-face 'front-sticky '(face))))
 
-  ;; Re-arm electric.
-  (setplist 'forms--electric '(modification-hooks (forms--romh)))
+       ;; Enable `post-command-hook' to restore the properties.
+       (setq post-command-hook
+             (append (list 'forms--iif-post-command-hook) post-command-hook)))
 
-  ;; Enable `post-command-hook' to restore the properties.
-  (setq post-command-hook
-       (append (list 'forms--romh-post-command-hook) post-command-hook)))
+    ;; No action needed.  Clear marker.
+    (setq forms--iif-start nil)))
 
-(defun forms--romh-post-command-hook ()
-  "`post-command-hook' function for forms--electric characters."
+(defun forms--iif-post-command-hook ()
+  "`post-command-hook' function for read-only segments."
 
   ;; Disable `post-command-hook'.
   (setq post-command-hook
-       (delq 'forms--romh-post-command-hook post-command-hook))
-
-  ;; Disarm modification hook.
-  (setplist 'forms--electric nil)
+       (delq 'forms--iif-hook-post-command-hook post-command-hook))
 
   ;; Restore properties.
-  (if forms--ro-modification-start
+  (if forms--iif-start
       (let ((inhibit-read-only t))
        (set-text-properties 
-        (1- forms--ro-modification-start) forms--ro-modification-start
-        forms--ro-properties)))
-
-  ;; Re-arm electric.
-  (setplist 'forms--electric '(modification-hooks (forms--romh)))
+        (1- forms--iif-start) forms--iif-start
+        forms--iif-properties)))
 
   ;; Cleanup.
-  (setq forms--ro-modification-start nil))
+  (setq forms--iif-start nil))
 \f
 (defvar forms--marker)
 (defvar forms--dyntext)
@@ -778,13 +767,18 @@ Commands (prefix with C-c if not in read-only mode):
      (if forms-use-text-properties 
         (` (lambda (arg)
              (let ((inhibit-read-only t))
-               (setplist 'forms--electric nil)
                (,@ (apply 'append
                           (mapcar 'forms--make-format-elt-using-text-properties
-                                  forms-format-list))))
-             (setplist 'forms--electric
-                       '(modification-hooks (forms--romh)))
-             (setq forms--ro-modification-start nil)))
+                                  forms-format-list)))
+               ;; Prevent insertion before the first text.
+               (,@ (if (numberp (car forms-format-list))
+                       nil
+                     '((add-text-properties (point-min) (1+ (point-min))
+                                            '(front-sticky (read-only))))))
+               ;; Prevent insertion after the last text.
+               (remove-text-properties (1- (point)) (point)
+                                       '(rear-nonsticky)))
+             (setq forms--iif-start nil)))
        (` (lambda (arg)
            (,@ (apply 'append
                       (mapcar 'forms--make-format-elt forms-format-list)))))))
@@ -803,47 +797,55 @@ Commands (prefix with C-c if not in read-only mode):
   ;; ;; preamble
   ;; (lambda (arg)
   ;;   (let ((inhibit-read-only t))
-  ;;     (setplist 'forms--electric nil)
   ;;
-  ;;     ;; a string, e.g. "text: "
+  ;;     ;; A string, e.g. "text: ".
   ;;     (set-text-properties 
   ;;      (point)
   ;;      (progn (insert "text: ") (point)) 
-  ;;      (list 'face forms--ro-face 'read-only 1))
+  ;;      (list 'face forms--ro-face
+  ;;           'read-only 1
+  ;;           'insert-in-front-hooks 'forms--iif-hook
+  ;;           'rear-nonsticky '(read-only face insert-in-front-hooks)))
   ;;
-  ;;     ;; a field, e.g. 6
+  ;;     ;; A field, e.g. 6.
   ;;     (let ((here (point)))
   ;;       (aset forms--markers 0 (point-marker))
   ;;       (insert (elt arg 5))
   ;;       (or (= (point) here)
   ;;     (set-text-properties 
   ;;      here (point)
-  ;;      (list 'face forms--rw-face)))
-  ;;       (if (get-text-property (1- here) 'read-only)
-  ;;     (put-text-property 
-  ;;      (1- here) here
-  ;;      'category 'forms--electric)))
+  ;;      (list 'face forms--rw-face
+  ;;            'front-sticky '(face))))
   ;;
-  ;;     ;; another string, e.g. "\nmore text: "
+  ;;     ;; Another string, e.g. "\nmore text: ".
   ;;     (set-text-properties
   ;;      (point)
   ;;      (progn (insert "\nmore text: ") (point))
   ;;      (list 'face forms--ro-face
-  ;;      'read-only 2))
+  ;;           'read-only 2
+  ;;           'insert-in-front-hooks 'forms--iif-hook
+  ;;           'rear-nonsticky '(read-only face insert-in-front-hooks)))
   ;;
-  ;;     ;; a function, e.g. (tocol 40)
+  ;;     ;; A function, e.g. (tocol 40).
   ;;     (set-text-properties
   ;;      (point)
   ;;      (progn
   ;;        (insert (aset forms--dyntexts 0 (tocol 40)))
   ;;        (point))
   ;;      (list 'face forms--ro-face
-  ;;      'read-only 2))
+  ;;           'read-only 2
+  ;;           'insert-in-front-hooks 'forms--iif-hook
+  ;;           'rear-nonsticky '(read-only face insert-in-front-hooks)))
+  ;;
+  ;;    ;; Prevent insertion before the first text.
+  ;;    (add-text-properties (point-min) (1+ (point-min))
+  ;;                         '(front-sticky (read-only))))))
+  ;;    ;; Prevent insertion after the last text.
+  ;;    (remove-text-properties (1- (point)) (point)
+  ;;                            '(rear-nonsticky)))
   ;;
   ;;     ;; wrap up
-  ;;     (setplist 'forms--electric
-  ;;         '(modification-hooks (forms--romh)))
-  ;;     (setq forms--ro-modification-start nil)
+  ;;     (setq forms--iif-start nil)
   ;;     ))
 
   (cond
@@ -855,7 +857,10 @@ Commands (prefix with C-c if not in read-only mode):
           (insert (, el))
           (point))
         (list 'face forms--ro-face     ; read-only appearance
-              'read-only (,@ (list (1+ forms--marker))))))))
+              'read-only (,@ (list (1+ forms--marker)))
+              'insert-in-front-hooks '(forms--iif-hook)
+              'rear-nonsticky '(face read-only insert-in-front-hooks))))))
+    
    ((numberp el)
     (` ((let ((here (point)))
          (aset forms--markers 
@@ -866,11 +871,8 @@ Commands (prefix with C-c if not in read-only mode):
          (or (= (point) here)
              (set-text-properties 
               here (point)
-              (list 'face forms--rw-face)))
-         (if (get-text-property (1- here) 'read-only)
-             (put-text-property
-              (1- here) here
-              'category 'forms--electric))))))
+              (list 'face forms--rw-face
+                    'front-sticky '(face))))))))
 
    ((listp el)
     (` ((set-text-properties
@@ -882,8 +884,9 @@ Commands (prefix with C-c if not in read-only mode):
                         (, el)))
           (point))
         (list 'face forms--ro-face
-              'read-only 
-              (,@ (list (1+ forms--marker))))))))
+              'read-only (,@ (list (1+ forms--marker)))
+              'insert-in-front-hooks '(forms--iif-hook)
+              'rear-nonsticky '(read-only face insert-in-front-hooks))))))
 
    ;; end of cond
    ))
@@ -1207,7 +1210,6 @@ Commands (prefix with C-c if not in read-only mode):
   (setq buffer-read-only nil)
   (if forms-use-text-properties
       (let ((inhibit-read-only t))
-       (setplist 'forms--electric nil)
        (set-text-properties (point-min) (point-max) nil)))
   (erase-buffer)
 
@@ -1291,11 +1293,10 @@ As a side effect: sets `forms--the-record-list'."
 
        (save-excursion
          (set-buffer forms--file-buffer)
-         ;; Insert something before kill-line is called.  See kill-line
-         ;; doc.  Bugfix provided by Ignatios Souvatzis.
-         (insert "*")
-         (beginning-of-line)
-         (kill-line nil)
+         ;; Use delete-region instead of kill-region, to avoid
+         ;; adding junk to the kill-ring.
+         (delete-region (save-excursion (beginning-of-line) (point))
+                        (save-excursion (end-of-line) (point)))
          (insert the-record)
          (beginning-of-line))))))
 
@@ -1499,7 +1500,10 @@ it is called to fill (some of) the fields with default values."
        (save-excursion
          (set-buffer forms--file-buffer)
          (goto-line ln)
-         (kill-line 1))
+         ;; Use delete-region instead of kill-region, to avoid
+         ;; adding junk to the kill-ring.
+         (delete-region (save-excursion (beginning-of-line) (point))
+                        (save-excursion (end-of-line) (1+ (point)))))
        (setq forms--total-records (1- forms--total-records))
        (if (> forms--current-record forms--total-records)
            (setq forms--current-record forms--total-records))