DESCRIPTION
A calculator which receives a boolean or arithmetic expression
as an argument, evaluates it and prints the result on standard
output. If a valid arithmetic expression is given, the numeric result
is printed on stdout and the program exits with 0. If a boolean
expression is given, clex is mute and conveys the result of
the evaluation to the caller via the return value:
0/1: expression evaluates to true/false.
REFERENCE
See evselect
documentation for the full list of available
arithmetic/boolean operators and functions.
