(Storing Variables): Mention `calc-copy-special-constant'.

1 files changed, 30 insertions, 19 deletions

diff --git a/man/calc.texi b/man/calc.texi
index 4cf16da1515..5d0af765f15 100644
--- a/man/calc.texi
+++ b/man/calc.texi
@@ -28298,6 +28298,15 @@ will be left alone even if you press @kbd{=} (@code{calc-evaluate}).
 The @kbd{s u} (@code{calc-unstore}) command returns a variable to the
 void state.
 
+@kindex s c
+@pindex calc-copy-variable
+The @kbd{s c} (@code{calc-copy-variable}) command copies the stored
+value of one variable to another.  One way it differs from a simple
+@kbd{s r} followed by an @kbd{s t} (aside from saving keystrokes) is
+that the value never goes on the stack and thus is never rounded,
+evaluated, or simplified in any way; it is not even rounded down to the
+current precision.
+
 The only variables with predefined values are the ``special constants''
 @code{pi}, @code{e}, @code{i}, @code{phi}, and @code{gamma}.  You are free
 to unstore these variables or to store new values into them if you like,
@@ -28307,25 +28316,26 @@ you change the value of one of these variables, or of one of the other
 special variables @code{inf}, @code{uinf}, and @code{nan} (which are
 normally void).
 
-Note that @code{pi} doesn't actually have 3.14159265359 stored
-in it, but rather a special magic value that evaluates to @cpi{}
-at the current precision.  Likewise @code{e}, @code{i}, and
-@code{phi} evaluate according to the current precision or polar mode.
-If you recall a value from @code{pi} and store it back, this magic
-property will be lost.
-
-@kindex s c
-@pindex calc-copy-variable
-The @kbd{s c} (@code{calc-copy-variable}) command copies the stored
-value of one variable to another.  It differs from a simple @kbd{s r}
-followed by an @kbd{s t} in two important ways.  First, the value never
-goes on the stack and thus is never rounded, evaluated, or simplified
-in any way; it is not even rounded down to the current precision.
-Second, the ``magic'' contents of a variable like @code{e} can
-be copied into another variable with this command, perhaps because
-you need to unstore @code{e} right now but you wish to put it
-back when you're done.  The @kbd{s c} command is the only way to
-manipulate these magic values intact.
+Note that @code{pi} doesn't actually have 3.14159265359 stored in it,
+but rather a special magic value that evaluates to @cpi{} at the current
+precision.  Likewise @code{e}, @code{i}, and @code{phi} evaluate
+according to the current precision or polar mode.  If you recall a value
+from @code{pi} and store it back, this magic property will be lost.  The
+magic property is preserved, however, when a variable is copied with
+@kbd{s c}.
+
+@kindex s k
+@pindex calc-copy-special-constant
+If one of the ``special constants'' is redefined (or undefined) so that
+it no longer has its magic property, the property can be restored with 
+@kbd{s k} (@code{calc-copy-special-constant}).  This command will prompt
+for a special constant and a variable to store it in, and so a special
+constant can be stored in any variable.  Here, the special constant that
+you enter doesn't depend on the value of the corresponding variable;
+@code{pi} will represent 3.14159@dots{} regardless of what is currently
+stored in the Calc variable @code{pi}.  If one of the other special
+variables, @code{inf}, @code{uinf} or @code{nan}, is given a value, its
+original behavior can be restored by voiding it with @kbd{s u}.
 
 @node Recalling Variables, Operations on Variables, Storing Variables, Store and Recall
 @section Recalling Variables
@@ -35615,6 +35625,7 @@ keystrokes are not listed in this summary.
 @r{       @:      s d   @:var, decl    @:        @:calc-declare-variable@:}
 @r{       @:      s e   @:var, editing @: 29,30  @:calc-edit-variable@:}
 @r{       @:      s i   @:buffer       @:        @:calc-insert-variables@:}
+@r{       @:      s k   @:const, var   @:    29  @:calc-copy-special-constant@:}
 @r{    a b@:      s l   @:var          @:    29  @:@:a  (letting var=b)}
 @r{  a ...@:      s m   @:op, var      @: 22,29  @:calc-store-map@:}
 @r{       @:      s n   @:var          @: 29,47  @:calc-store-neg@:  (v/-1)}