The PREDICATE() macros has a number of variations that deal with
special cases.
- PREDICATE0(name)
- This is the same as PREDICATE(name, 0). It avoids a compiler warning
about that
PL_av is not used.
- NAMED_PREDICATE(plname,
cname, arity)
- This version can be used to create predicates whose name is not a valid
C++ identifier. Here is a ---hypothetical--- example, which unifies the
second argument with a stringified version of the first. The‘cname'
is used to create a name for the functions. The concrete name does not
matter, but must be unique. Typically it is a descriptive name using the
limitations imposed by C++ indentifiers.
NAMED_PREDICATE("#", hash, 2)
{ A2 = (wchar_t*)A1;
}
- NAMED_PREDICATE_NONDET(plname,
cname, arity)
- Define a non-deterministic Prolog predicate in C++. See
SWI-cpp.h. FIXME: Needs cleanup and an example.