OVERVIEW

The interface has two panels. The left panel combines status information with context-sensitive help; the right panel represents the calculator's stack. (Note that the left panel will be hidden if Orpie is run in a terminal with less than 80 columns.)

In general, you perform calculations by first entering data on to the stack, then executing functions that operate on the stack data. As an example, you can hit 1<enter>2<enter>+ in order to add 1 and 2.

ENTERING REAL NUMBERS

To enter a real number, just type the desired digits and hit enter. The space bar will begin entry of a scientific notation exponent. The 'n' key is used for negation. Here are some examples:

ENTERING COMPLEX NUMBERS

Orpie can represent complex numbers using either cartesian (rectangular) or polar coordinates. See PERFORMING BASIC COMMAND OPERATIONS to see how to change the complex number display mode.

A complex number is entered by first pressing '(', then entering the real part, then pressing ',' followed by the imaginary part. Alternatively, you can press '(' followed by the magnitude, then '<' followed by the phase angle. The angle will be interpreted in degrees or radians, depending on the current setting of the angle mode (see PERFORMING BASIC COMMAND OPERATIONS). Examples:

ENTERING MATRICES

You can enter matrices by pressing '['. The elements of the matrix may then be entered as described in the previous sections, and should be separated using ','. To start a new row of the matrix, press '[' again. On the stack, each row of the matrix is enclosed in a set of brackets; for example, the matrix

would appear on the stack as [[1, 2][3, 4]].

Examples of matrix entry:

ENTERING DATA WITH UNITS

Real and complex scalars and matrices can optionally be labeled with units. After typing in the numeric portion of the data, press '_' followed by a units string. The format of units strings is described in the UNITS FORMATTING section.

Examples of entering dimensioned data:

ENTERING EXACT INTEGERS

An exact integer may be entered by pressing '#' followed by the desired digits. The base of the integer will be assumed to be the same as the current calculator base mode (see PERFORMING BASIC COMMAND OPERATIONS to see how to set this mode). Alternatively, the desired base may be specified by pressing space and appending one of {b, o, d, h}, to represent binary, octal, decimal, or hexadecimal, respectively. On the stack, the representation of the integer will be changed to match the current base mode. Examples:

Note that exact integers may have unlimited length, and the basic arithmetic operations (addition, subtraction, multiplication, division) will be performed using exact arithmetic when both arguments are integers.

ENTERING VARIABLE NAMES

A variable name may be entered by pressing '@' followed by the desired variable name string. The string may contain alphanumeric characters, dashes, and underscores. Example:

Orpie also supports autocompletion of variable names. The help panel displays a list of pre-existing variables that partially match the name currently being entered. You can press '<tab>' to iterate through the list of matching variables.

As a shortcut, keys <f1>-<f4> will enter the variables (``registers'') @ r01 through @ r04.

ENTERING PHYSICAL CONSTANTS

Orpie includes definitions for a number of fundamental physical constants. To enter a constant, press 'C', followed by the first few letters/digits of the constant's symbol, then hit enter. Orpie offers an autocompletion feature for physical constants, so you only need to type enough of the constant to identify it uniquely. A list of matching constants will appear in the left panel of the display, to assist you in finding the desired choice.

The following is a list of Orpie's physical constant symbols:

All physical constants are defined in the Orpie run-configuration file; consult the orpierc(5) manpage if you wish to define your own constants or change the existing definitions.

ENTERING DATA WITH AN EXTERNAL EDITOR

Orpie can also parse input entered via an external editor. You may find this to be a convenient method for entering large matrices. Pressing 'E' will launch the external editor, and the various data types may be entered as illustrated by the examples below:

Real and complex numbers and matrices may have units appended; just add a units string such as ``_N*m/s'' immediately following the numeric portion of the expression.

Notice that the complex matrix input parser is quite flexible; real and complex matrix elements may be mixed, and cartesian and polar complex formats may be mixed as well.

Multiple stack entries may be specified in the same file, if they are separated by whitespace. For example, entering (1, 2) 1.5 into the editor will cause the complex value (1, 2) to be placed on the stack, followed by the real value 1.5.

The input parser will discard whitespace where possible, so feel free to add any form of whitespace between matrix rows, matrix elements, real and complex components, etc.

EXECUTING BASIC FUNCTION OPERATIONS

Once some data has been entered on the stack, you can apply operations to that data. For example, '+' will add the last two elements on the stack. By default, the following keys have been bound to such operations:

As a shortcut, function operators will automatically enter any data that you were in the process of entering. So instead of the sequence 2<enter>2<enter>+, you could type simply 2<enter>2+ and the second number would be entered before the addition operation is applied.

As an additional shortcut, any variable names used as function arguments will be evaluated before application of the function. In other words, it is not necessary to evaluate variables before performing arithmetic operations on them.

EXECUTING FUNCTION ABBREVIATIONS

One could bind nearly all calculator operations to specific keypresses, but this would rapidly get confusing since the PC keyboard is not labeled as nicely as a calculator keyboard is. For this reason, Orpie includes an abbreviation syntax.

To activate an abbreviation, press ''' (quote key), followed by the first few letters/digits of the abbreviation, then hit enter. Orpie offers an autocompletion feature for abbreviations, so you only need to type enough of the operation to identify it uniquely. The matching abbreviations will appear in the left panel of the display, to assist you in finding the appropriate operation.

To avoid interface conflicts, abbreviations may be entered only when the entry buffer (the bottom line of the screen) is empty.

The following functions are available as abbreviations:

Entering abbreviations can become tedious when performing repetitive calculations. To save some keystrokes, Orpie will automatically bind recently-used operations with no prexisting binding to keys <f5>-<f12>. The current autobindings can be viewed by pressing 'h' to cycle between the various pages of the help panel.

EXECUTING BASIC COMMAND OPERATIONS

In addition to the function operations listed in the section EXECUTING BASIC FUNCTION OPERATIONS, a number of basic calculator commands have been bound to single keypresses:

EXECUTING COMMAND ABBREVIATIONS

In addition to the function operations listed in the section EXECUTING FUNCTION ABBREVIATIONS, there are a large number of calculator commands that have been implemented using the abbreviation syntax:

BROWSING THE STACK

Orpie offers a stack browsing mode to assist in viewing and manipulating stack data. Press <up> to enter stack browsing mode; this should highlight the last stack element. You can use the up and down arrow keys to select different stack elements. The following keys are useful in stack browsing mode:

The left and right scrolling option may prove useful for viewing very lengthy stack entries, such as large matrices. The edit option provides a convenient way to correct data after it has been entered on the stack.

UNITS FORMATTING

A units string is a list of units separated by '*' to indicate multiplication and '/' to indicate division. Units may be raised to real-valued powers using the '^'character. A contrived example of a valid unit string would be "N*nm^2*kg/s/in^-3*GHz^2.34".

Orpie supports the standard SI prefix set, {y, z, a, f, p, n, u, m, c, d, da, h, k, M, G, T, P, E, Z, Y} (note the use of 'u' for micro-). These prefixes may be applied to any of the following exhaustive sets of units:

Note: No, Celsius and Fahrenheit will not be supported. Because these temperature units do not share a common zero point, their behavior is ill-defined under many operations.

Note: Although the lumen is defined by 1_lm = 1_cd * sr, Orpie drops the steridian because it is a dimensionless unit and therefore is of questionable use to a calculator.

All units are defined in the Orpie run-configuration file; consult the orpierc(5) manpage if you wish to define your own units or change the existing definitions.