1.7 and
| (and expr expr expr ...) |
The exprs are evaluated from left to right. If the first
expr evaluates to false, the and expression
immediately evaluates to false. If the first expr
evaluates to true, the next expression is considered. If all
exprs evaluate to true, the and expression
evaluates to true. If any of the expressions evaluate to a
value other than true or false, it is an error.