Boolean is a built-in type.  It implements conventional Boolean operations.
It has signature:

    Boolean: type B {
      (* constants *)
        False:  func [] val B;
        True:   func [] val B;
      (* operations *)
        := :    func [var B; val B] val B;
        <> :    func [x,y: val B] val B;
        = :     func [x,y: val B] val B;
        New:    func [] var B;
	New:    func [val B] var B;   (* initializes to arg value *)
        V:      func [var B] val B;
        and:    func [x,y:val B] val B;
        not:    func [val B] val B;
        or:     func [x,y:val B] val B;
        put:    func [val B] val B;
        puts:   func [val B] val ChStr;
    };

The put function writes "True" or False" on the standard output file.
The "puts" function returns either "True" or "False".

Implementation note:  The 'and' and 'or' are functions are detrimental
to the performance of the peephole optimizer.  The cand and cor constructs
are usually preferred.  The implementation of Boolean values is
compatible with C.

See also: cand