NAME
xcalc - scientific calculator for X

SYNOPSIS
xcalc [-stipple] [-rpn] [-toolkitoption...]

DESCRIPTION
xcalc is a scientific calculator desktop accessory that can
emulate a TI-30 or an HP-10C.

OPTIONS
xcalc accepts all of the standard toolkit command line
options along with two additional options:

-stipple
This option indicates that the background of the
calculator should be drawn using a stipple of the
foreground and background colors. On monochrome
displays improves the appearance.

-rpn This option indicates that Reverse Polish Notation
should be used. In this mode the calculator will
look and behave like an HP-10C. Without this flag,
it will emulate a TI-30.

OPERATION
Pointer Usage: Operations may be performed with pointer but-
ton 1, or in some cases, with the keyboard. Many common cal-
culator operations have keyboard accelerators. To quit,
press pointer button 3 on the AC key of the TI calculator,
or the ON key of the HP calculator.

Calculator Key Usage (TI mode): The numbered keys, the +/-
key, and the +, -, *, /, and = keys all do exactly what you
would expect them to. It should be noted that the operators
obey the standard rules of precedence. Thus, entering
"3+4*5=" results in "23", not "35". The parentheses can be
used to override this. For example, "(1+2+3)*(4+5+6)="
results in "6*15=90".

The entire number in the calculator display can be selected,
in order to paste the result of a calculation into text.

The action procedures associated with each function are
given below. These are useful if you are interested in
defining a custom calculator. The action used for all digit
keys is digit(n), where n is the corresponding digit, 0..9.

1/x Replaces the number in the display with its
reciprocal. The corresponding action procedure is
reciprocal().

x^2 Squares the number in the display. The
corresponding action procedure is square().

SQRT Takes the square root of the number in the
display. The corresponding action procedure is
squareRoot().

CE/C When pressed once, clears the number in the
display without clearing the state of the machine.
Allows you to re-enter a number if you make a mis-
take. Pressing it twice clears the state, also.
The corresponding action procedure for TI mode is
clear().

AC Clears the display, the state, and the memory.
Pressing it with the third pointer button turns
off the calculator, in that it exits the program.
The action procedure to clear the state is off();
to quit, quit().

INV Invert function. See the individual function keys
for details. The corresponding action procedure
is inverse().

sin Computes the sine of the number in the display, as
interpreted by the current DRG mode (see DRG,
below). If inverted, it computes the arcsine.
The corresponding action procedure is sine().

cos Computes the cosine, or arccosine when inverted.
The corresponding action procedure is cosine().

tan Computes the tangent, or arctangent when inverted.
The corresponding action procedure is tangent().

DRG Changes the DRG mode, as indicated by ’DEG’,
’RAD’, or ’GRAD’ at the bottom of of the calcula-
tor "liquid crystal" display. When in ’DEG’
mode, numbers in the display are taken as being
degrees. In ’RAD’ mode, numbers are in radians,
and in ’GRAD’ mode, numbers are in grads. When
inverted, the DRG key has a feature of converting
degrees to radians to grads and vice-versa. Exam-
ple: put the calculator into ’DEG’ mode, and
enter "45 INV DRG". The display should now show
something along the lines of ".785398", which is
45 degrees converted to radians. The correspond-
ing action procedure is degree().

e The constant ’e’. (2.7182818...). The
corresponding action procedure is e().

EE Used for entering exponential numbers. For exam-
ple, to get "-2.3E-4" you’d enter "2 . 3 +/- EE 4
+/-". The corresponding action procedure is
scientific().

log Calculates the log (base 10) of the number in the
display. When inverted, it raises "10.0" to the
number in the display. For example, entering "3
INV log" should result in "1000". The correspond-
ing action procedure is logarithm().

ln Calculates the log (base e) of the number in the
display. When inverted, it raises "e" to the
number in the display. For example, entering "e
ln" should result in "1". The corresponding
action procedure is naturalLog().

y^x Raises the number on the left to the power of the
number on the right. For example "2 y^x 3 ="
results in "8", which is 2^3. For a further exam-
ple, "(1+2+3) y^x (1+2) =" equals "6 y^x 3" which
equals "216". The corresponding action procedure
is power().

PI The constant ’pi’. (3.1415927....) The
corresponding action procedure is pi().

x! Computes the factorial of the number in the
display. The number in the display must be an
integer in the range 0-500, though, depending on
your math library, it might overflow long before
that. The corresponding action procedure is fac-
torial().

( Left parenthesis. The corresponding action pro-
cedure for TI calculators is leftParen().

) Right parenthesis. The corresponding action pro-
cedure for TI calculators is rightParen().

/ Division. The corresponding action procedure is
divide().

* Multiplication. The corresponding action pro-
cedure is multiply().

- Subtraction. The corresponding action procedure
is subtract().

+ Addition. The corresponding action procedure is
add().

= Perform calculation. The TI-specific action pro-
cedure is equal().

STO Copies the number in the display to the memory
location. The corresponding action procedure is
store().

RCL Copies the number from the memory location to the
display. The corresponding action procedure is
recall().

SUM Adds the number in the display to the number in
the memory location. The corresponding action
procedure is sum().

EXC Swaps the number in the display with the number in
the memory location. The corresponding action
procedure for the TI calculator is exchange().

+/- Negate; change sign. The corresponding action
procedure is negate().

. Decimal point. The action procedure is decimal().

Calculator Key Usage (RPN mode): The number keys, CHS
(change sign), +, -, *, /, and ENTR keys all do exactly what
you would expect them to do. Many of the remaining keys are
the same as in TI mode. The differences are detailed below.
The action procedure for the ENTR key is enter().

<- This is a backspace key that can be used if you
make a mistake while entering a number. It will
erase digits from the display. (See BUGS).
Inverse backspace will clear the X register. The
corresponding action procedure is back().

ON Clears the display, the state, and the memory.
Pressing it with the third pointer button turns
off the calculator, in that it exits the program.
To clear state, the action procedure is off; to
quit, quit().

INV Inverts the meaning of the function keys. This
would be the f key on an HP calculator, but xcalc
does not display multiple legends on each key.
See the individual function keys for details.

10^x Raises "10.0" to the number in the top of the
stack. When inverted, it calculates the log (base
10) of the number in the display. The correspond-
ing action procedure is tenpower().

e^x Raises "e" to the number in the top of the stack.
When inverted, it calculates the log (base e) of
the number in the display. The action procedure
is epower().

STO Copies the number in the top of the stack to a
memory location. There are 10 memory locations.
The desired memory is specified by following this
key with a digit key.

RCL Pushes the number from the specified memory loca-
tion onto the stack.

SUM Adds the number on top of the stack to the number
in the specified memory location.

x:y Exchanges the numbers in the top two stack posi-
tions, the X and Y registers. The corresponding
action procedure is XexchangeY().

R v Rolls the stack downward. When inverted, it rolls
the stack upward. The corresponding action pro-
cedure is roll().

blank These keys were used for programming functions on
the HP-10C. Their functionality has not been
duplicated in xcalc.

Finally, there are two additional action procedures: bell(),
which rings the bell; and selection(), which performs a cut
on the entire number in the calculator’s "liquid crystal"
display.

ACCELERATORS
Accelerators are shortcuts for entering commands. xcalc
provides some sample keyboard accelerators; also users can
customize accelerators. The numeric keypad accelerators
provided by xcalc should be intuitively correct. The
accelerators defined by xcalc on the main keyboard are given
below:

TI Key HP Key Keyboard Accelerator TI Function HP Function

SQRT SQRT r squareRoot() squareRoot()
AC ON space clear() clear()
AC <- Delete clear() back()
AC <- Backspace clear() back()
AC <- Control-H clear() back()
AC Clear clear()
AC ON q quit() quit()
AC ON Control-C quit() quit()

INV i i inverse() inverse()
sin s s sine() sine()
cos c c cosine() cosine()
tan t t tangent() tangent()
DRG DRG d degree() degree()

e e e()
ln ln l naturalLog() naturalLog()
y^x y^x ^ power() power()

PI PI p pi() pi()
x! x! ! factorial() factorial()
( ( leftParen()
) ) rightParen()

/ / / divide() divide()
* * * multiply() multiply()
- - - subtract() subtract()
+ + + add() add()
= = equal()

0..9 0..9 0..9 digit() digit()
. . . decimal() decimal()
+/- CHS n negate() negate()

x:y x XexchangeY()
ENTR Return enter()
ENTR Linefeed enter()

CUSTOMIZATION
The application class name is XCalc.

xcalc has an enormous application defaults file which speci-
fies the position, label, and function of each key on the
calculator. It also gives translations to serve as keyboard
accelerators. Because these resources are not specified in
the source code, you can create a customized calculator by
writing a private application defaults file, using the
Athena Command and Form widget resources to specify the size
and position of buttons, the label for each button, and the
function of each button.

The foreground and background colors of each calculator key
can be individually specified. For the TI calculator, a
classical color resource specification might be:

XCalc.ti.Command.background: gray50
XCalc.ti.Command.foreground: white

For each of buttons 20, 25, 30, 35, and 40, specify:
XCalc.ti.button20.background: black
XCalc.ti.button20.foreground: white

For each of buttons 22, 23, 24, 27, 28, 29, 32, 33, 34, 37,
38, and 39:
XCalc.ti.button22.background: white
XCalc.ti.button22.foreground: black

WIDGET HIERARCHY
In order to specify resources, it is useful to know the
hierarchy of the widgets which compose xcalc. In the
notation below, indentation indicates hierarchical struc-
ture. The widget class name is given first, followed by the
widget instance name.

XCalc xcalc
Form ti or hp (the name depends on the mode)
Form bevel
Form screen
Label M
Toggle LCD
Label INV
Label DEG
Label RAD
Label GRAD
Label P
Command button1
Command button2
Command button3
and so on, ...
Command button38
Command button39
Command button40

APPLICATION RESOURCES
rpn (Class Rpn)
Specifies that the rpn mode should be used. The
default is TI mode.

stipple (Class Stipple)
Indicates that the background should be stippled.
The default is "on" for monochrome displays, and
"off" for color displays.

cursor (Class Cursor)
The name of the symbol used to represent the
pointer. The default is "hand2".

COLORS
If you would like xcalc to use its ti colors, include the
following in the #ifdef COLOR section of the file you read
with xrdb:

*customization: -color

This will cause xcalc to pick up the colors in the app-
defaults color customization file: <XRoot>/lib/X11/app-
defaults/XCalc-color.

SEE ALSO
X(1), xrdb(1), the Athena Widget Set

BUGS
HP mode: A bug report claims that the sequence of keys 5,
ENTER, <- should clear the display, but it doesn’t.

AUTHORS
John Bradley, University of Pennsylvania
Mark Rosenstein, MIT Project Athena
Donna Converse, MIT X Consortium