crpn - A simple command-line calculator

This is a simple reverse polish notation (RPN) calculator for use in a command-line terminal.

It's essentially a ground-up rewrite of my desktop calculator, NeRPN, which is still a neat example of a Swing Java application and works well enough if you're looking for a graphical (but minimal) RPN calculator.

This version is written in pure Python and should run just about anywhere. It can be used over SSH in a pure terminal environment, and of course, will use the colors and fonts you have set in your terminal.

1. Installing it
2. Using it
3. Other things to try
4. List of operations
5. License

Installing it

As a user, the easiest way is to install is from pypi:

pip install crpn

Alternatively, to install from the downloaded repo, use the included Makefile:

make install

Using it

1. Run it by typing crpn at the command-prompt. It will provide a few instructions and show you the stack, which will initially be empty:

    ===================================================
    crpn v.0.2.0 - a minimalist command-line calculator
    ===================================================
    
    Enter values on the stack, or the name of an operation or command.
    
    Type 'quit' or 'exit' to quit.  Type 'help' for help.
    
    Current stack:
    ------------------------
    ------------------------
    > 
   

2. Type values (either integer or floating-point) and press Enter to add them to the stack.

    > 10
    ------------------------
     0:   10
    ------------------------
    > 2
    ------------------------
     1:   10
     0:   2
    ------------------------
   

3. Type operations (+, -, *, /, !, ^, cos, abs, etc.) to operate on stack members and see the results of the calculation.

    > ^
    ------------------------
     0:   100
    ------------------------
   

4. Type quit or exit to save the stack and quit.

Other things to try

• Type help commands or help operations for a list of all current operations.

• Type help or help <op_name> to get general help or help for a specific operation at any time.

• Press Enter without entering a value to duplicate the final row on the stack.

• Type del or del <n> to delete stack row(s), or clear to clear the stack

• You can combine operations with &&. For example, to clear the stack and then quit, type:

    > clear && quit
  

List of operations

(generated using help operations)

• 'abs' - Compute the absolute value of row 0.
• 'acos' - Compute the arccosine of row 0.
• 'add' - Add rows 0 and 1 together.
• 'asin' - Compute the arcsine of row 0.
• 'atan' - Compute the arctangent of row 0.
• 'cbrt' - Compute the cube root of row 0.
• 'ceil' - Compute the ceiling (next higher whole number) for row 0.
• 'clear' - Clear the stack.
• 'cos' - Compute the cosine of row 0.
• 'cosh' - Compute the hyperbolic cosine of row 0.
• 'deg' - Converts the radian value on row 0 to degrees
• 'del' - Delete row 0, or the row specified by the optional argument.
• 'div' - Divide row 1 by row 0.
• 'dup' - Duplicate row 0 and add it to the stack.
• 'e' - Raise the constant 'e' to the power of the value on row 0.
• 'en1' - Raise the constant 'e' to the power of 1/value on row 0.
• 'eng' - Display results in engineering notation.
• 'exp' - Raise 10 to the power of the value on row 0.
• 'expn1' - Raise 10 to the power of 1/value on row 0.
• 'fact' - Compute the factorial of row 0.
• 'fix' - Display results in fixed-point notation.
• 'floor' - Compute the floor (next lower whole number) for row 0.
• 'help' - Print general help, or for a given operation.
• 'hyp' - Computes the hypoteneuse (sqrt(x2 + y2)) of rows 0 and 1.
• 'inv' - Computes the inverse (1/x) of row 0.
• 'ln' - Computes the natural (e-based) log of row 0.
• 'log' - Computes the 10-based log of row 0.
• 'max' - Computes the max between row 0 and 1, or between the number of rows specified in the optional argument.
• 'min' - Computes the min between row 0 and 1, or between the number of rows specified in the optional argument.
• 'mult' - Multiply rows 0 and 1.
• 'neg' - Negate row 0.
• 'pow' - Raise row 1 to the power of row 2.
• 'quit' - Save the current state and quit.
• 'rad' - Convert the value of row 0 (in degrees) to radians.
• 'rand' - Add a random fractional value to the stack.
• 'root' - Computes the x root of y for rows 0 and 1.
• 'rot' - Rotates rows 0-2, or the number of rows specified in the optional argument.
• 'sci' - Display results in scientific notation.
• 'sin' - Compute the sine of row 0.
• 'sinh' - Compute the hyperbolic sine of row 0.
• 'sqrt' - Compute the square root of row 0.
• 'std' - Display results in standard notation.
• 'subt' - Subtract row 0 from row 1.
• 'sum' - Sum all rows, or a given number of them, together.
• 'swap' - Swap rows 0 and 1, or row 0 with the one provided in the optional parameter.
• 'tan' - Compute the tangent of row 0.
• 'tanh' - Compute the hyperbolic tangent of row 0.

To get built-in help for any of these operations, type help <op_name>.

License

This code is provided under the MIT license. You are free to use it for any purpose, but I assume no liability and offer no warranty. See the LICENSE file for full details.