There are a small number of built-in types that are directly supported through primitives and syntax:
Integers and floats are provided with primitives for performing arithmetic operations, comparisons etc.
Strings have a byte vector part for storing the characters. Special string primitives are provided.
Blocks are objects which combine code with an environment link. Used for control structures, they are described in section [2.1.7].
In addition, there are a number of VM-supported types described in the sections on the Self World and the VM reference manual, such as mirrors, processes, vectors, proxies and profilers.