+2009-07-21 Jay Belanger <jay.p.belanger@gmail.com>
+
+ * calc.texi (Undoing Mistakes): Mention that the undo list will be
+ truncated when Calc is quit.
+ (Customizing Calc): Document `calc-undo-length'.
+
2009-07-20 Chong Yidong <cyd@stupidchicken.com>
* calc.texi (About This Manual): Don't mention chapter numbers in text.
queried whether or not to restore the variable to its original value.
The @kbd{U} key may be pressed any number of times to undo successively
farther back in time; with a numeric prefix argument it undoes a
-specified number of operations. The undo history is cleared only by the
-@kbd{q} (@code{calc-quit}) command. (Recall that @kbd{C-x * c} is
-synonymous with @code{calc-quit} while inside the Calculator; this
-also clears the undo history.)
+specified number of operations. When the Calculator is quit, as with
+the @kbd{q} (@code{calc-quit}) command, the undo history will be
+truncated to the length of the customizable variable
+@code{calc-undo-length} (@pxref{Customizing Calc}), which by default
+is @expr{100}. (Recall that @kbd{C-x * c} is synonymous with
+@code{calc-quit} while inside the Calculator; this also truncates the
+undo history.)
Currently the mode-setting commands (like @code{calc-precision}) are not
undoable. You can undo past a point where you changed a mode, but you
of @code{calc-multiplication-has-precedence} is @code{t}.
@end defvar
+@defvar calc-undo-length
+The variable @code{calc-undo-length} determines the number of undo
+steps that Calc will keep track of when @code{calc-quit} is called.
+If @code{calc-undo-length} is a non-negative integer, then this is the
+number of undo steps that will be preserved; if
+@code{calc-undo-length} has any other value, then all undo steps will
+be preserved. The default value of @code{calc-undo-length} is @expr{100}.
+@end defvar
+
@node Reporting Bugs, Summary, Customizing Calc, Top
@appendix Reporting Bugs
+2009-07-21 Jay Belanger <jay.p.belanger@gmail.com>
+
+ * calc/calc.el (calc-undo-length): New variable.
+ (calc-quit): Truncate rather than eliminate `calc-undo-list'.
+
2009-07-21 Richard Stallman <rms@gnu.org>
* files.el (auto-save-mode): Handle buffer-save-size = -2