Expression types are categorized as primitive or derived. Primitive expression types include variables and procedure calls. Derived expression types are not semantically primitive, but can instead be defined as macros.

The procedures force, promise?, make-promise, and make-parameter are also described in this chapter because they are intimately associated with the delay, delay-force, and parameterize expression types.

husk-scheme online documentation rev 3.19.3 (2016.07.10)