entered into RCS

1 files changed, 52 insertions, 48 deletions

diff --git a/lispref/backups.texi b/lispref/backups.texi
index 28da97ee46c..7944b7361b2 100644
--- a/lispref/backups.texi
+++ b/lispref/backups.texi
@@ -60,7 +60,7 @@ saving the buffer the first time.
   This buffer-local variable indicates whether this buffer's file has
 been backed up on account of this buffer.  If it is non-@code{nil}, then
 the backup file has been written.  Otherwise, the file should be backed
-up when it is next saved (if backup files are enabled).  This is a
+up when it is next saved (if backups are enabled).  This is a
 permanent local; @code{kill-local-variables} does not alter it.
 @end defvar
 
@@ -86,12 +86,12 @@ which may save disk space.  (You would put this code in your
 @end smallexample
 @end defopt
 
-@defvar backup-enable-predicate filename
+@defvar backup-enable-predicate
 This variable's value is a function to be called on certain occasions to
-decide whether a there should be backup files for file name
-@var{filename}.  If it returns @code{nil}, backups are disabled.
-Otherwise, the other variables in this section say whether and how to
-make backups.
+decide whether a file should have backup files.  The function receives
+one argument, a file name to consider.  If the function returns
+@code{nil}, backups are disabled for that file.  Otherwise, the other
+variables in this section say whether and how to make backups.
 
 The default value is this:
 
@@ -107,8 +107,11 @@ The default value is this:
 If this variable is non-@code{nil}, backups are inhibited.  It records
 the result of testing @code{backup-enable-predicate} on the visited file
 name.  It can also coherently be used by other mechanisms that inhibit
-backups based on which file is visited.  Major modes should not set this
-variable.
+backups based on which file is visited.  This is a permanent local,
+so that changing the major mode does not lose its value.
+
+Major modes should not set this variable---they should set
+@code{make-backup-files} instead.
 @end defvar
 
 @node Rename or Copy
@@ -194,16 +197,16 @@ otherwise, do not.
 Do not make numbered backups.
 
 @item @var{anything else}
-Do make numbered backups.
+Make numbered backups.
 @end table
 @end defopt
 
   The use of numbered backups ultimately leads to a large number of
 backup versions, which must then be deleted.  Emacs can do this
-automatically.
+automatically or it can ask the user whether to delete them.
 
 @defopt kept-new-versions
-The value of this variable is the number of oldest versions to keep
+The value of this variable is the number of newest versions to keep
 when a new numbered backup is made.  The newly made backup is included
 in the count.  The default value is 2.
 @end defopt
@@ -216,7 +219,7 @@ when a new numbered backup is made.  The default value is 2.
   If there are backups numbered 1, 2, 3, 5, and 7, and both of these
 variables have the value 2, then the backups numbered 1 and 2 are kept
 as old versions and those numbered 5 and 7 are kept as new versions;
-backup version 3 is deleted.  The function @code{find-backup-file-name}
+backup version 3 is excess.  The function @code{find-backup-file-name}
 (@pxref{Backup Names}) is responsible for determining which backup
 versions to delete, but does not delete them itself.
 
@@ -229,7 +232,7 @@ them.
 @defopt dired-kept-versions
 This variable specifies how many of the newest backup versions to keep
 in the Dired command @kbd{.} (@code{dired-clean-directory}).  That's the
-same thing @code{kept-new-versions} does when you make a new backup
+same thing @code{kept-new-versions} specifies when you make a new backup
 file.  The default value is 2.
 @end defopt
 
@@ -278,7 +281,7 @@ to redefine for customization.
 @end defun
 
 @defun make-backup-file-name filename
-This function returns a string which is the name to use for a
+This function returns a string that is the name to use for a
 non-numbered backup file for file @var{filename}.  On Unix, this is just
 @var{filename} with a tilde appended.
 
@@ -293,9 +296,9 @@ The standard definition of this function is as follows:
 @end group
 @end smallexample
 
-You can change the backup file naming convention by redefining this
+You can change the backup-file naming convention by redefining this
 function.  The following example redefines @code{make-backup-file-name}
-to prepend a @samp{.} as well as appending a tilde:
+to prepend a @samp{.} in addition to appending a tilde:
 
 @smallexample
 @group
@@ -337,10 +340,10 @@ version that the caller should consider deleting now.
 @c Emacs 19 feature
 @defun file-newest-backup filename
 This function returns the name of the most recent backup file for
-@var{filename}, or @code{nil} that file has no backup files.
+@var{filename}, or @code{nil} if that file has no backup files.
 
-Some file comparison commands use this function in order to compare
-a file by default with its most recent backup.
+Some file comparison commands use this function so that they can
+automatically compare a file with its most recent backup.
 @end defun 
 
 @node Auto-Saving
@@ -419,8 +422,8 @@ correspondingly.
 This function returns the file name to use for auto-saving the current
 buffer.  This is just the file name with hash marks (@samp{#}) appended
 and prepended to it.  This function does not look at the variable
-@code{auto-save-visited-file-name}; you should check that before calling
-this function.
+@code{auto-save-visited-file-name} (described below); you should check
+that before calling this function.
 
 @example
 @group
@@ -458,7 +461,7 @@ change @code{auto-save-file-name-p} in a corresponding way.
 @defvar auto-save-visited-file-name
 If this variable is non-@code{nil}, Emacs auto-saves buffers in
 the files they are visiting.  That is, the auto-save is done in the same
-file which you are editing.  Normally, this variable is @code{nil}, so
+file that you are editing.  Normally, this variable is @code{nil}, so
 auto-save files have distinct names that are created by
 @code{make-auto-save-file-name}.
 
@@ -535,15 +538,15 @@ nothing.
 @end defun
 
 @defvar buffer-saved-size
-The value of this buffer-local variable is the former length of the
-current buffer, as of the last time it was read in, saved or auto-saved.
-This is used to detect a substantial decrease in size, and turn off
-auto-saving in response.
+The value of this buffer-local variable is the length of the current
+buffer as of the last time it was read in, saved, or auto-saved.  This is
+used to detect a substantial decrease in size, and turn off auto-saving
+in response.
 
 If it is -1, that means auto-saving is temporarily shut off in this
 buffer due to a substantial deletion.  Explicitly saving the buffer
 stores a positive value in this variable, thus reenabling auto-save.
-Turning Auto-Save mode off or on also alters this variable.
+Turning auto-save mode off or on also alters this variable.
 @end defvar
 
 @node Reverting
@@ -571,33 +574,34 @@ the buffer; but if the argument @var{noconfirm} is non-@code{nil},
 @code{revert-buffer} does not ask for confirmation.
 
 Reverting tries to preserve marker positions in the buffer by using the
-replacement feature of @code{insert-file-contents}.  If there is no
-actual difference between the buffer and the file, before reversion,
-this preserves all the markers.  If reversion does change the buffer,
-this preserves the markers in the unchanged text (if any) at the
-beginning and end of the buffer.  Preserving any additional markers
-would be problematical.
-
-If the value of the @code{revert-buffer-function} variable is
-non-@code{nil}, it is called as a function with no arguments to do the
-work.
+replacement feature of @code{insert-file-contents}.  If the buffer
+contents and the file contents are identical before the revert
+operation, reverting preserves all the markers.  If they are not
+identical, reverting does change the buffer; then it preserves the
+markers in the unchanged text (if any) at the beginning and end of the
+buffer.  Preserving any additional markers would be problematical.
 @end deffn
 
+You can customize how @code{revert-buffer} does its work by setting
+these variables---typically, as buffer-local variables.
+
 @defvar revert-buffer-function
-The value of this variable is the function to use to revert this
-buffer; but if the value of this variable is @code{nil}, then the
-@code{revert-buffer} function carries out its default action.  Modes
-such as Dired mode, in which the text being edited does not consist of a
-file's contents but can be regenerated in some other fashion, give this
-variable a buffer-local value that is a function to regenerate the
-contents.
+The value of this variable is the function to use to revert this buffer.
+If non-@code{nil}, it is called as a function with no arguments to do
+the work of reverting.  If the value is @code{nil}, reverting works the
+usual way.
+
+Modes such as Dired mode, in which the text being edited does not
+consist of a file's contents but can be regenerated in some other
+fashion, give this variable a buffer-local value that is a function to
+regenerate the contents.
 @end defvar
 
 @defvar revert-buffer-insert-file-contents-function
-The value of this variable, if non-@code{nil}, is the function to use
-to insert contents when reverting this buffer.  The function receives
-two arguments, first the file name to use, and second, @code{t} if the
-user has asked to read the auto-save file.
+The value of this variable, if non-@code{nil}, is the function to use to
+insert contents when reverting this buffer.  The function receives two
+arguments, first the file name to use; second, @code{t} if the user has
+asked to read the auto-save file.
 @end defvar
 
 @defvar before-revert-hook