variable is really just an Emacs Lisp variable that contains a Calc number
or formula.) A variable's name is normally composed of letters and digits.
Calc also allows apostrophes and @code{#} signs in variable names.
-The Calc variable @code{foo} corresponds to the Emacs Lisp variable
-@code{var-foo}. Commands like @kbd{s s} (@code{calc-store}) that operate
-on variables can be made to use any arbitrary Lisp variable simply by
-backspacing over the @samp{var-} prefix in the minibuffer.
+(The Calc variable @code{foo} corresponds to the Emacs Lisp variable
+@code{var-foo}, but unless you access the variable from within Emacs
+Lisp, you don't need to worry about it.)
In a command that takes a variable name, you can either type the full
name of a variable, or type a single digit to use one of the special
-convenience variables @code{var-q0} through @code{var-q9}. For example,
-@kbd{3 s s 2} stores the number 3 in variable @code{var-q2}, and
+convenience variables @code{q0} through @code{q9}. For example,
+@kbd{3 s s 2} stores the number 3 in variable @code{q2}, and
@w{@kbd{3 s s foo @key{RET}}} stores that number in variable
-@code{var-foo}.
+@code{foo}.
To push a variable itself (as opposed to the variable's value) on the
stack, enter its name as an algebraic expression using the apostrophe
-(@key{'}) key. Variable names in algebraic formulas implicitly have
+(@key{'}) key.
+
+xxx
+ Variable names in algebraic formulas implicitly have
@samp{var-} prefixed to their names. The @samp{#} character in variable
names used in algebraic formulas corresponds to a dash @samp{-} in the
Lisp variable name. If the name contains any dashes, the prefix @samp{var-}
turn into the @code{assign} function, which Calc normally displays
using the @samp{:=} symbol.
-The variables @code{var-pi} and @code{var-e} would be displayed @samp{pi}
+The variables @code{pi} and @code{e} would be displayed @samp{pi}
and @samp{e} in Normal mode, but in C mode they are displayed as
@samp{M_PI} and @samp{M_E}, corresponding to the names of constants
typically provided in the @file{<math.h>} header. Functions whose
If your system does not have a suitable @samp{date} command, you
may wish to put a @samp{(setq var-TimeZone ...)} in your Emacs
-initialization file to set the time zone. The easiest way to do
+initialization file to set the time zone. (Since you are interacting
+with the variable @code{TimeZone} directly from Emacs Lisp, the
+@code{var-} prefix needs to be present.) The easiest way to do
this is to edit the @code{TimeZone} variable using Calc's @kbd{s T}
command, then use the @kbd{s p} (@code{calc-permanent-variable})
command to save the value of @code{TimeZone} permanently.
The @kbd{s s} (@code{calc-store}) command stores the value at the top of
the stack into a specified variable. It prompts you to enter the
name of the variable. If you press a single digit, the value is stored
-immediately in one of the ``quick'' variables @code{var-q0} through
-@code{var-q9}. Or you can enter any variable name. The prefix @samp{var-}
-is supplied for you; when a name appears in a formula (as in @samp{a+q2})
-the prefix @samp{var-} is also supplied there, so normally you can simply
-forget about @samp{var-} everywhere. Its only purpose is to enable you to
-use Calc variables without fear of accidentally clobbering some variable in
-another Emacs package. If you really want to store in an arbitrary Lisp
-variable, just backspace over the @samp{var-}.
+immediately in one of the ``quick'' variables @code{q0} through
+@code{q9}. Or you can enter any variable name.
@kindex s t
@pindex calc-store-into
special variables @code{inf}, @code{uinf}, and @code{nan} (which are
normally void).
-Note that @code{var-pi} doesn't actually have 3.14159265359 stored
+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{var-e}, @code{var-i}, and
-@code{var-phi} evaluate according to the current precision or polar mode.
+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.
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{var-e} can
+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{var-e} right now but you wish to put it
+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.
use a different file instead of @file{.emacs}.)
If you do not specify the name of a variable to save (i.e.,
-@kbd{s p @key{RET}}), all @samp{var-} variables with defined values
+@kbd{s p @key{RET}}), all Calc variables with defined values
are saved except for the special constants @code{pi}, @code{e},
@code{i}, @code{phi}, and @code{gamma}; the variables @code{TimeZone}
and @code{PlotRejects};
@kindex s i
@pindex calc-insert-variables
The @kbd{s i} (@code{calc-insert-variables}) command writes
-the values of all @samp{var-} variables into a specified buffer.
-The variables are written in the form of Lisp @code{setq} commands
+the values of all Calc variables into a specified buffer.
+The variables are written with the prefix @code{var-} in the form of
+Lisp @code{setq} commands
which store the values in string form. You can place these commands
in your @file{.emacs} buffer if you wish, though in this case it
would be easier to use @kbd{s p @key{RET}}. (Note that @kbd{s i}
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