What is a truth table evaluator?

A truth table evaluator is a computer program that evaluates a truth table, i.e., it produces the truth value of a statement for all possible values of its variables.

There are at least a few on the web:

Brian Borowski's TT Constructor (http://www.brian-borowski.com/index.html)

Joole (http://stephan-brumme.com/programming/Joole/)

Orion Transfer TT Evaluator (http://svn.oriontransfer.org/TruthTable/)

Lawrence Turner's TT Evaluator (http://turner.faculty.swau.edu/mathematics/materialslibrary/truth/)