bool

Bool(ean) data-type. Values are either the tokens True or False.

Operators defined on booleans:

• bool0 && bool1: Evaluate bool0. If evaluated bool0 is false, return false, otherwise evaluate bool1 and return evaluated bool1.

• bool0 || bool1: Evaluate bool. If evaluated bool0 is true, return true, otherwise evaluate bool1 and return evaluated bool1.

• ! bool0: Evaluate bool0. IF evaluated bool0 is true, return False, otherwise return True.

• expr0 == expr1: Return true, if expr0 and expr1 are True. Also return True, if expr0 and expr1 are False. In all othercases False is returned.

• expr0 != expr1: Returns the same as
  ! ( expr0 == expr1 )