A program to handle simple logic predicates

A predicate has clauses, which are strings of upper and lower case characters,
and boolean operators, which can be conjunction ("&," "&&," " AND ", " and ")
disjunction, ("|" "||," " OR ", " or "), and exclusive-disjunction ("+," "++," " XOR ", " xor ").
Note that the words must be surrounded by spaces. That is, "XANDY" is simply one clause,
whereas "X AND Y" is the same as "X & Y".
Other characters are ignored.

Choose boolean symbols to use:                    

Enter a predicate:

Jeff Offutt