138: Highlights
- A predicate is a method that answers
true or false.
- The
not message answers false when sent to true,
and true when sent to false.
- If you want to compare two numbers, then use predicates such as
=, ~ =, >, <, >=, or <=.
- If you want to determine whether an instance is a member of a particular
class, then use predicates such as
isInteger and isString.
