Calc is an interactive calculator which provides for easy large
numeric caluclations, but which also can be easily programmed for
difficult or long calculations. It can accept a command line
argument, in which case it executes that single command and exits.
Otherwise it enters interactive mode. In this mode, it accepts
commands one at a time, processes them, and displays the answers.
In the simplest case, commands are simply expressions which are
evaluated. For example, he following line can be input:
> 3 * (4 + 1)
and the calculator will print 15.

Commands are statements in a C-like language, where each input line
is treated as the body of a procedure. Thus he copmmand line can
contain variable declarations, expressions, labels, conditional
tests, and loops. Assignments to any variable name will automatically
define that name as a global variable.

For more information on the program, run 'calc help help'.

Homepage:
http://www.isthe.com/chongo/tech/comp/calc/
