(with-category-table): Use `make-symbol' to avoid variable capture.

Set table within `unwind-protect'.  Ensure table is restored in
correct buffer.  Add docstring.  Basically, copy `with-syntax-table'.

2 files changed, 23 insertions, 7 deletions

diff --git a/lisp/ChangeLog b/lisp/ChangeLog
index 8a92d0d6b71..a7e5e0b7023 100644
--- a/lisp/ChangeLog
+++ b/lisp/ChangeLog
@@ -1,3 +1,9 @@
+2003-03-29  John Paul Wallington  <jpw@gnu.org>
+
+        * international/mule.el (with-category-table): Use `make-symbol'
+        to avoid variable capture.  Set table within `unwind-protect'.
+        Ensure table is restored in correct buffer.  Add docstring.
+
 2003-03-29  Kenichi Handa  <handa@etlken2>
 
         * language/japan-util.el: If system-type is not for Windows,
diff --git a/lisp/international/mule.el b/lisp/international/mule.el
index d5e516ee059..0d96510edf8 100644
--- a/lisp/international/mule.el
+++ b/lisp/international/mule.el
@@ -593,7 +593,7 @@ character code range.  Thus FUNC should iterate over [START, END]."
                  (make-char charset (+ i start) (+ start chars -1)))))))
 
 (defun register-char-codings (coding-system safe-chars)
-  "This is an obsolete function.  
+  "This is an obsolete function.
 It exists just for backward compatibility, and it does nothing.")
 (make-obsolete 'register-char-codings
                "Unnecessary function.  Calling it has no effect."
@@ -1985,12 +1985,22 @@ the table in `translation-table-vector'."
 
 (put 'with-category-table 'lisp-indent-function 1)
 
-(defmacro with-category-table (category-table &rest body)
-  `(let ((current-category-table (category-table)))
-     (set-category-table ,category-table)
-     (unwind-protect
-         (progn ,@body)
-       (set-category-table current-category-table))))
+(defmacro with-category-table (table &rest body)
+  "Evaluate BODY with category table of current buffer set to TABLE.
+The category table of the current buffer is saved, BODY is evaluated,
+then the saved table is restored, even in case of an abnormal exit.
+Value is what BODY returns."
+  (let ((old-table (make-symbol "old-table"))
+        (old-buffer (make-symbol "old-buffer")))
+    `(let ((,old-table (category-table))
+           (,old-buffer (current-buffer)))
+       (unwind-protect
+           (progn
+             (set-category-table ,table)
+             ,@body)
+         (save-current-buffer
+           (set-buffer ,old-buffer)
+           (set-category-table ,old-table))))))
 
 (defun define-translation-hash-table (symbol table)
   "Define SYMBOL as the name of the hash translation TABLE for use in CCL.