Required Declaration of C Function Parameters

[Doug Gwyn <gwyn>]

Although the syntax of recursive type declaration can be made
simpler (as in the Cedar example), one will still run into
problems when type-checking recursive types unless some trick
similar in concept to the example I gave is used.  Note that
the idea of having two types of entity whose "useful" property
is the same but which have a different additional property for
cutting recursion short is commonly used, for example in the
axioms of a set theory free from Russell antinomies.  It is
possible to embed the recursion-truncation in an algorithm
in such a way that the two "levels" are not obvious, but they
are always there.