Reverse Polish Notation Calculator, version 1.00.
Copyleft (L) 2019 - Thomas von Dein.
Licensed under the terms of the GPL 3.0.

Commandline: rpn [-d] [<operator>]

If <operator> is provided, read numbers from STDIN,
otherwise runs interactively.

Available commands:
c    clear stack
s    show the stack
d    toggle debugging (current setting: 0)
r    reverse the stack (w/ reg if stack==1)
u    undo last operation
q    finish
?    print help

Available operators:
+    add
-    substract
/    divide
*    multiply
^    expotentiate
%    percent
&    bitwise AND
|    bitwise OR
x    bitwise XOR