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Primitives

RL admits some special terms that receive special treatment.

Every term has an associated type. This potentially infinite regress is broken by the special term ^ROOT, which is the root of the type system and is its own type.

There is a special term ANY that, as a pattern, matches any subject. There is also a term NONE that, as a pattern, does not match any subject. We can summarize this as follows, where t and u are arbitrary terms that are not NONE or ANY.

pattern subject
ANY t NONE
ANY match match match
u no match u ~ t no match
NONE no match no match no match